JP2010244725A - Nonaqueous electrolyte battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve sealing properties of an electrode terminal lead portion in a nonaqueous electrolyte battery sheathed by a sheath material such as a laminated film. <P>SOLUTION: The first and second step difference parts are provided at a portion from which an electrode terminal of the nonaqueous electrolyte battery is led out, thereby sealing the sheath material. The first and second step difference parts are formed by being divided into two steps and sealed using two heater blocks equipped with notched parts having different widths. A convex part formed by the notched part of a first heater block is pressed by the notched part of the second heater block, thereby forming the second step difference part. Then, the convex part formed by the notched part of the first heater block is pressed by a portion except the notched part of the second heater block, thereby forming the first step difference part. The sealing properties can be improved by filling molten resin into voids remaining in the vicinity of the electrode terminal when sealed by the first heater block by forming the second step difference part. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to, for example, a non-aqueous electrolyte battery, and more particularly to a non-aqueous electrolyte battery that is packaged with a laminate film and has good sealing properties.

  In recent years, many portable electronic devices such as a camera-integrated VTR (Videotape Recorder), a mobile phone, or a laptop computer have appeared, and their size and weight have been reduced. Along with this, the demand for batteries used as power sources for portable electronic devices is growing rapidly, and the battery design is light and thin, and the storage space in the devices is used efficiently to realize downsizing of the devices. It is demanded. As a battery satisfying such requirements, a lithium ion secondary battery having a large energy density and output density is most suitable.

  In order to realize a thin lithium ion secondary battery, for example, a battery element in which a strip-like positive electrode and a negative electrode are stacked via a separator and these are wound in an approximately elliptical shape is used. Alternatively, an element structure in which a flat positive electrode, a separator, and a flat negative electrode are used as basic stack units and a plurality of the basic stack units are stacked may be employed. The battery element is packaged with a laminate film or the like together with a nonaqueous electrolyte. The non-aqueous electrolyte battery manufactured in this way can easily take out the positive electrode terminal and the negative electrode terminal from each basic laminate unit, so that the internal current collecting resistance is reduced while maintaining a simple structure and high productivity. Can be realized.

  As described above, a metal laminate film (hereinafter referred to as a laminate film as appropriate) can be employed as an exterior material for enclosing the battery element. The laminate film has a basic structure of a laminate in which resin layers are formed on both surfaces of a metal foil. For this reason, the weight can be significantly reduced as compared with a metal outer can.

  The battery element is covered with a laminate film and sealed by heat-sealing the laminate films around the battery element. The laminated film is heat-sealed by, for example, a metal heater block. A heater block having a notch provided in consideration of the thickness of the positive electrode terminal and the negative electrode terminal is used for the terminal lead-out side where the positive electrode terminal and the negative electrode terminal are led out of the battery element. The notch is provided at a position facing the positive terminal and the negative terminal of the heater block.

  The sealing process in the electrode terminal derivation | leading edge of a battery element is demonstrated using FIG. FIG. 1 is a cross-sectional view of the electrode terminal lead-out portion of the battery element.

  As shown in FIG. 1A, sealants 2a and 2b, which are sealing members, are provided at portions of the positive electrode terminal 1a and the negative electrode terminal 1b facing the laminate film 7. This is to improve the adhesion between the positive electrode terminal 1 a and the negative electrode terminal 1 b and the laminate film 7. Hereinafter, the positive electrode terminal 1a and the negative electrode terminal 1b are appropriately referred to as the electrode terminal 1 unless particularly limited. Further, hereinafter, the sealants 2a and 2b are appropriately referred to as the sealant 2 when not specifically limited.

  Laminate films 7 are positioned above and below the positive electrode terminal 1a and the negative electrode terminal 1b, respectively. A heater block 10 is arranged so as to sandwich the laminate film 7. At least one of the heater blocks 10 is provided with notches 10a and 10b in accordance with the positions of the positive electrode terminal 1a and the negative electrode terminal 1b.

  As shown in FIG. 1B, the laminate film 7 is sandwiched between the heater blocks 10, and resin layers (not shown) formed inside the laminate film 7 are melted and fused together by heat. At this time, the notched portions 10a and 10b of the heater block 10 prevent the pressure from being excessively applied to the portions where the positive terminal 1a and the negative terminal 1b are led out. Thereby, as shown to FIG. 1C, the part which is not derived | led-out of the positive electrode terminal 1a and the negative electrode terminal 1b is heated and pressurized by the heater block 10, and the laminate films 7 are firmly heat-sealed. The portions where the positive electrode terminal 1a and the negative electrode terminal 1b are led out are heated by the heater block 10, and the laminate film 7, the positive electrode terminal 1a, and the negative electrode terminal 1b are thermally fused to each other.

  However, as shown in FIGS. 1B and 1C, when such a method is used, a gap is generated between the laminate film 7 and the sealants 2a and 2b. When a gap is generated between the laminate film 7 and the sealants 2a and 2b, the sealing performance of the battery is lowered.

  This is because the widths of the notches 10a and 10b of the heater block 10 are set sufficiently wide with respect to the widths of the positive electrode terminal 1a and the negative electrode terminal 1b, and the widths of the sealants 2a and 2b are set as narrow as possible. It is because it tends to be. The reason why the widths of the notches 10a and 10b of the heater block 10 are set to be wide is that even when the positions of the positive electrode terminal 1a and the negative electrode terminal 1b vary, the heater block 10 is positively connected to the positive electrode terminal 1a. This is to prevent the negative electrode terminal 1b from being sandwiched. The reason why the widths of the sealants 2a and 2b are set narrow is to reduce interference with a protective circuit board (not shown) connected to the positive electrode terminal 1a and the negative electrode terminal 1b led out of the battery.

  Further, as shown in FIG. 2, when the pressing force of the heater block 10 is too strong, the heat-sealing layer 7a of the laminate film 7 located at the portion pressed by the heater block 10 is melted, and the molten resin is vigorous. It is often pushed out to the electrode terminal 1 side. As a result, there arises a problem that the end of the sealant 2 is swung by the momentum of the molten resin. The sealant 2 is not completely melted at the time of sealing by the heater block 10, but often maintains a film shape although the surface is in a semi-molten state. For this reason, the above problems arise. In FIG. 2, the laminate film 7 is shown as a heat sealing layer 7a, a metal layer 7b, and a surface protective layer 7c.

  When the sealant 2 is swung, the effect of the sealant 2 that improves the sealing effect in the vicinity of the electrode terminal 1 is diminished. Further, for example, the melted resin cannot enter into the void generated in the bent portion of the sealant 2, and the void may remain. The air gap remaining in the shading portion of the sealant 2 may lead to, for example, the passage of moisture from the outside or leakage of the electrolyte from the inside of the battery to the outside. Moreover, the problem that the sealing part in the vicinity of this space | gap will tear easily arises. Further, there arises a problem that the sealing performance of the electrode terminal lead-out portion varies depending on the state of the sealant 2.

  Conventionally, with respect to such a problem of gaps, the resin layer inside the laminate film is melted and fluidized by the heat and pressure of the heater block at the time of sealing to fill the gaps. Further, as in Patent Document 1 below, a method for narrowing the width of the notch portion of the heater block has been proposed.

JP 2002-298800 A

  However, in the method of filling the gap by the flow of molten resin, the gap may not be filled due to variations in the positions of the positive electrode terminal and the negative electrode terminal and the sealing conditions. When the gap is not filled, the gap becomes a path through which the electrolyte leaks from the inside of the battery. Moreover, it becomes a moisture infiltration path from the outside of the battery, gas is generated inside the battery, and the battery swells.

  Further, in the method of reducing the width of the notch portion of the heater block, it is difficult to prevent interference between the heater block, the positive electrode terminal, and the negative electrode terminal, and there is a high possibility that the positive electrode terminal and the negative electrode terminal are damaged. Even when there is no interference between the heater block and the positive electrode terminal and the negative electrode terminal, the portion where the electrode terminal is led out may be compressed to the same extent as other sealing parts, which may reduce the sealing performance. There is. Moreover, the positive electrode terminal and / or the negative electrode terminal and the metal foil (not shown) constituting the laminate film may be short-circuited by the compression of the heater block, and the battery element may be damaged.

  Therefore, an object of the present invention is to improve the sealing performance of a nonaqueous electrolyte battery covered with a laminate film without causing damage or short circuit of the positive electrode terminal and / or the negative electrode terminal.

In order to solve the problem, the first invention includes a battery element having a positive electrode, a negative electrode, a positive electrode terminal connected to the positive electrode, and a negative electrode terminal connected to the negative electrode;
A non-aqueous electrolyte,
A metal layer, a surface protective layer made of a first resin material formed on one surface of the metal layer, and a heat fusion layer made of a second resin material formed on the other surface of the metal layer, It consists of an exterior material in which a recess is formed from the heat sealing layer side toward the surface protective layer side,
A sealing member is provided in a portion facing the exterior material of the positive electrode terminal and the negative electrode terminal,
The battery element is housed in the recess and the battery element is packaged in the exterior material, and the positive electrode terminal and the negative electrode terminal are sandwiched between the heat-sealing layers of the exterior material through the sealing member and led out of the exterior material,
In the lead-out portion of the positive electrode terminal and the negative electrode terminal, a first step portion and a second step portion are provided,
The thickness of the first step portion is 105% or more with respect to the thickness of the sealing portion other than the lead portion of the positive electrode terminal and the negative electrode terminal and 90% or less with respect to the thickness of the second step portion,
The lengths of the first step portion and the second step portion in the positive electrode terminal and negative electrode terminal lead-out direction are not less than 0.3 mm and not more than the length of the sealing portion,
The width of the second stepped portion is wider than the width of the positive electrode terminal and the negative electrode terminal, and 20% or more of the difference between the width of the first stepped portion and the width of the sealing member is narrower than the width of the first stepped portion. It is a non-aqueous electrolyte battery.

A second invention has a positive electrode, a negative electrode, a positive electrode terminal connected to the positive electrode, and a negative electrode terminal connected to the negative electrode, and a battery in which a sealing member is provided in part of the positive electrode terminal and the negative electrode terminal The element includes a metal layer, a surface protective layer made of a first resin material formed on one surface of the metal layer, and a heat fusion layer made of a second resin material formed on the other surface of the metal layer. And is accommodated in a recess of the exterior material in which a recess is formed from the heat sealing layer side to the surface protective layer side so that the positive electrode terminal and the negative electrode terminal are sandwiched between the heat sealing layer via the sealing member. And exterior steps to exterior,
A first sealing step of heat-sealing at least one side excluding one side other than the electrode terminal lead-out side and the electrode terminal lead-out side from which the positive electrode terminal and the negative electrode terminal are derived;
The first heater block having a first cutout portion and a second cutout portion having a width wider than the width of the sealing member causes the first cutout portion and the second cutout portion to be a positive electrode terminal and a negative electrode. A second sealing step of thermally fusing the electrode terminal lead-out side so as to face the terminals,
More than 20% of the difference between the width of the first notch and the second notch and the width of the sealing member that is wider than the width of the positive electrode terminal and the negative electrode terminal, and the first notch and the second notch Using the second heater block having a third cutout portion and a fourth cutout portion that are narrower than the width of the cutout portion, the third cutout portion and the fourth cutout portion become the positive electrode terminal and the negative electrode terminal. A third sealing step of forming first and second step portions in the lead-out portions of the positive electrode terminal and the negative electrode terminal by thermally fusing the electrode terminal lead-out sides so as to face each other;
A non-aqueous electrolyte battery manufacturing method comprising a fourth sealing step in which one side that is not sealed other than the electrode terminal lead-out side is heat-sealed.

  In the first invention and the second invention, it is possible to prevent a gap from remaining between the sealing member bonded to each of the positive electrode terminal and the negative electrode terminal and the exterior material that covers the battery element.

  According to this invention, the sealing performance of the electrode terminal lead-out portion of the nonaqueous electrolyte battery can be improved, moisture intrusion from the outside of the battery and leakage of the electrolytic solution can be prevented, and the sealing portion can be prevented from being cleaved. .

It is sectional drawing which shows the sealing process in the conventional electrode terminal derivation | leading-out part. It is sectional drawing which shows the problem at the time of the conventional sealing. It is a basic diagram which shows the example of 1 structure of the nonaqueous electrolyte battery produced by applying this invention. It is the top view and sectional drawing which show the example of 1 structure of the electrode terminal derivation | leading-out part of the nonaqueous electrolyte battery produced by applying this invention. It is sectional drawing which shows one structural example of the electrode terminal derivation | leading-out part of the nonaqueous electrolyte battery produced by applying this invention. It is a top view which shows the example of 1 structure of the electrode terminal derivation | leading-out part of the nonaqueous electrolyte battery produced by applying this invention. It is a top view which shows the example of 1 structure of the electrode terminal derivation | leading-out part of the nonaqueous electrolyte battery produced by applying this invention. It is a top view which shows the example of 1 structure of the electrode terminal derivation | leading-out part of the nonaqueous electrolyte battery produced by applying this invention. It is sectional drawing which shows one structural example of the exterior material of the nonaqueous electrolyte battery produced by applying this invention. It is process drawing which shows an example of the manufacturing process of the nonaqueous electrolyte battery of this invention. It is sectional drawing which shows one structural example of the electrode terminal derivation | leading-out part in the manufacturing process of the nonaqueous electrolyte battery of this invention. It is a basic diagram which shows an example of the manufacturing process of the nonaqueous electrolyte battery of this invention. It is a top view which shows the problem in the manufacturing process of the nonaqueous electrolyte battery of this invention. It is sectional drawing which shows the example of 1 structure of the electrode terminal derivation | leading-out part of the nonaqueous electrolyte battery of this invention.

Hereinafter, the best mode for carrying out the invention (hereinafter referred to as an embodiment) will be described. The description will be made as follows.
1. 1st Embodiment (example which seals electrode terminal derivation | leading-out part in two steps)

<1. First Embodiment>
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

(1-1) Configuration of Nonaqueous Electrolyte Battery In this invention, the battery element is packaged with a laminate film to form a nonaqueous electrolyte battery. Hereinafter, the lead-out sides of the positive electrode terminal and the negative electrode terminal in the nonaqueous electrolyte battery are appropriately referred to as a top portion, the side facing the top portion is referred to as a bottom portion, and the side portion sandwiched between the top portion and the bottom portion is appropriately referred to as a side portion. In the following, a nonaqueous electrolyte battery using a battery element having a winding structure will be described. However, the present invention is not limited to this, and any thin battery element having a laminated structure or a zigzag folded structure may be used. It can be applied to both.

  FIG. 3 shows a configuration of a nonaqueous electrolyte battery 30 manufactured by applying the present invention. FIG. 3A is an external view of the nonaqueous electrolyte battery 30. FIG. 3B is a schematic diagram showing a state in which the battery element 20 is covered with the laminate film 23.

  The non-aqueous electrolyte battery 30 is manufactured by sealing a peripheral portion of the battery element 20 in which the battery element 20 is housed in a battery element housing portion 24 that is a recess formed in the laminate film 23. ing. The laminate film 23 has a heat fusion layer made of a resin material on the surface facing the battery element 20. Then, by sandwiching the laminate film 23 in which the heat fusion layers are opposed to each other with a heater block made of metal or the like, the heat fusion layers are melted and bonded. The detailed configuration of the laminate film 23 will be described later.

[Configuration of battery element]
Hereinafter, the configuration of the battery element 20 will be described.

  The battery element 20 is formed by sequentially laminating a strip-shaped positive electrode, a separator, a strip-shaped negative electrode disposed facing the positive electrode, and a separator, and is wound in the longitudinal direction. From the battery element 20, a positive electrode terminal 21 a connected to the positive electrode and a negative electrode terminal 21 b connected to the negative electrode (hereinafter referred to as the electrode terminal 21 when not referring to a specific terminal) are derived. Between the positive electrode terminal 21a and the negative electrode terminal 21b and the laminate film 23, sealants 22a and 22b (hereinafter referred to as the sealant 22 as appropriate) are arranged as sealing members for improving adhesiveness. . The sealant can be a resin film made of, for example, polypropylene (PP). Moreover, you may use the resin film which consists of a modified resin material with high adhesiveness with the electrode terminal which consists of metals.

  In the present invention, as shown in FIG. 4A, when sealing the top portion of the nonaqueous electrolyte battery, a first heater block (notch portions provided at positions facing the positive electrode terminal 21a and the negative electrode terminal 21b) ( The laminate film 23 is sealed with an unillustrated). The first heater block is preferably sealed over a region from the opening end of the battery element accommodating portion 24 provided in the laminate film 23 to the end of the laminate film 27. Thereby, the laminate films 23 are heat-sealed. Further, the interface portion between the laminate film 23 and the sealant 22 is also heat-sealed.

  Subsequently, the top portion is heat-sealed again with a second heater block having a notch portion with a narrower width. At this time, as shown in FIG. 3B, the first step portion 25 and the second step portion 26 are formed. At this time, the second step portion 26 is formed at a position facing the notch portion of the second heater block. And the 1st level | step-difference part 25 is formed in the position facing parts other than the notch part of a 2nd heater block. Thereby, it is possible to prevent a gap from being formed between the sealants 22 a and 22 b and the laminate film 23. By performing resealing with the second heater block, the voids remaining after sealing with the first heater block are filled with molten resin.

  In this invention, after the top part except the vicinity of the electrode terminal 21 is reliably heat-sealed by the first heater block, the vicinity of the electrode terminal 21 is heat-sealed by the second heater book. The molten resin flows by being pressed and heated by the second heater block, and a gap that is likely to be generated between the sealant 22 and the laminate film 23 after the heat fusion by the first heater block can be filled. Thereby, the top part of the nonaqueous electrolyte battery 30 is reliably heat-sealed, and the sealing property of the nonaqueous electrolyte battery 30 is enhanced.

  In the nonaqueous electrolyte battery 30 of the present invention, as shown in FIG. 5, the sealing part thickness of the sealing part where the positive electrode terminal 21a and the negative electrode terminal 21b are not led out is defined as a sealing part thickness T1. The sealing portion thickness of the first step portion 25 formed by being pressed by the second heater block is defined as a step thickness T2. The sealing portion thickness of the second step portion 26 formed by the notch portion of the second heater block and formed thicker than the first step portion 25 is defined as a notch portion thickness T3.

  In the present invention, the step thickness T2 is preferably 105% or more with respect to the sealing portion thickness T1. The step thickness T2 is preferably 90% or less with respect to the notch thickness T3.

  As shown in FIGS. 6A and 6B, the width W2 of the second stepped portion is set to be wider than the width WL of the electrode terminal 21 and slightly narrower than the width W1 of the first stepped portion. Among them, as shown in FIG. 6A, the width W2 of the second stepped portion is preferably wider than the width WL of the electrode terminal 21 and not more than the width WS of the sealant 22. Or as shown to FIG. 6B, it is good also as a range wider than the width | variety WS of the sealant 22, and narrower than the width | variety W1 of a 1st level | step-difference part. In this case, the width W2 of the second stepped portion is set to be 20% or more of the difference between the width W1 of the first stepped portion and the width WS of the sealant 22 and narrower than the width W1 of the first stepped portion. preferable. This is because if the width W2 of the second stepped portion is too close to the width W1 of the first stepped portion, a gap may remain between the sealant 22 and the laminate film 23.

  Furthermore, as shown in FIG. 7A, the length L of the first step portion 25 and the second step portion 26 is preferably equal to the length LS of the sealing portion. 7B, the length L of the first step portion 25 and the second step portion 26 may be shorter than the length LS of the sealing portion. In this case, the length L of the first step portion 25 and the second step portion 26 is preferably 0.3 mm or more. When the length L of the first step portion 25 and the second step portion 26 is less than 0.3 mm, the gap is not sufficiently filled with the molten resin, and the sealing performance may be lowered.

  As described above, by setting the thickness and length of the first step portion and the second step portion in the positive terminal lead portion and the negative terminal lead portion appropriately, the sealing property in the vicinity of the electrode terminal lead portion is improved. It can be certain.

  8A and 8B are top views of the top portion of the nonaqueous electrolyte battery 30 (particularly, the lead-out portion of the positive electrode terminal 21a). FIG. 8A schematically shows a hatched portion of the laminated film where the resin layer is melted and bonded at the time after sealing with the first heater block. FIG. 8B schematically shows the portion where the resin layer of the laminate film is melted and bonded at the time after sealing by the second heater block, with hatched portions.

  The portion of the first heater block facing the notch is heat-sealed with a narrow sealing width by the resin that has melted and flowed when heated and pressurized by the first heater block. The resin melted by the first heater block flows into a region beside the sealant 22a that is relatively less pressurized by the first heater block. The resin that has flowed in the direction of the positive electrode terminal 21a by the first heater block and the resin that has flowed from the positive electrode terminal 21a side are connected in a region beside the sealant 22a, and the laminate film 23 is sealed.

  In the top part of the non-aqueous electrolyte battery 30 in FIG. In the portion where the sealing width is narrow, the sealing portion is cleaved with less pressure than the other sealing portions. In addition, when the amount of resin flow is small, there is a possibility that the region adjacent to the sealant 22 is not sealed.

  And by sealing again with a 2nd heater block, the resin which fuse | melted enters the above-mentioned space | gap part. Thereby, the sealing width in the area | region of the side of the sealant 22 spreads, and it can make it harder to cleave a sealing part.

  Moreover, since the top part of the nonaqueous electrolyte battery 30 is further heated by the second heater block, the sealant 22 and the heat-sealing layer are sufficiently melted, and the adhesiveness can be further improved.

  Hereinafter, each part which comprises the nonaqueous electrolyte battery 30 is demonstrated in detail.

[Positive electrode]
In the positive electrode, a positive electrode active material layer containing a positive electrode active material is formed on both surfaces of a positive electrode current collector. As the positive electrode current collector, for example, a metal foil such as an aluminum (Al) foil, a nickel (Ni) foil, or a stainless steel (SUS) foil can be used.

The positive electrode active material layer includes, for example, a positive electrode active material, a conductive agent, and a binder. As the positive electrode active material, a metal oxide, a metal sulfide, or a specific polymer can be used depending on the type of the target battery. For example, in the case of constituting a lithium ion battery, Li _x MO ₂ (wherein M represents one or more transition metals, and x varies depending on the charge / discharge state of the battery, and is usually 0.05 or more and 1.10 or less. ) And a composite oxide of lithium and transition metal. As a transition metal constituting the lithium composite oxide, cobalt (Co), nickel (Ni), manganese (Mn), or the like is used.

Specific examples of such a lithium composite oxide include LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , LiNi _y Co _1-y O ₂ (0 <y <1). A solid solution in which a part of the transition metal element is substituted with another element can also be used. Examples thereof include LiNi _0.5 Co _0.5 O ₂ and LiNi _0.8 Co _0.2 O ₂ . These lithium composite oxides can generate a high voltage and have an excellent energy density. _{Furthermore, TiS 2, MoS 2, NbSe} 2, V 2 O no lithium metal sulfides such as ₅ or may be used an oxide as the positive electrode active material. These positive electrode active materials may be used alone or in combination of two or more.

  As the conductive agent, for example, a carbon material such as carbon black or graphite is used. As the binder, for example, polyvinylidene fluoride, polytetrafluoroethylene or the like is used.

  The positive electrode 21 has a positive electrode terminal 21a connected to one end of the positive electrode current collector by spot welding or ultrasonic welding. The positive electrode terminal 21a is preferably a metal foil or mesh-like one, but there is no problem even if it is not a metal as long as it is electrochemically and chemically stable and can conduct electricity. Examples of the material of the positive electrode terminal 21a include aluminum (Al) and nickel (Ni).

[Negative electrode]
In the negative electrode, a negative electrode active material layer containing a negative electrode active material is formed on both surfaces of a negative electrode current collector. As the negative electrode current collector, for example, a metal foil such as a copper (Cu) foil, a nickel foil, or a stainless steel foil can be used.

The negative electrode active material layer includes, for example, a negative electrode active material and, if necessary, a conductive agent and a binder. As the negative electrode active material, lithium metal, a lithium alloy, a carbon material that can be doped / undoped with lithium, or a composite material of a metal material and a carbon material is used. Specific examples of the carbon material that can be doped / undoped with lithium include graphite, non-graphitizable carbon, and graphitizable carbon. More specifically, pyrolytic carbons, cokes (pitch coke, needle coke, petroleum coke), graphites, glassy carbons, organic polymer compound fired bodies (phenolic resin, furan resin, etc.) at an appropriate temperature. Carbon materials such as those obtained by firing and carbonization), carbon fibers, activated carbon, and the like can be used. Furthermore, as a material that can be doped / undoped with lithium, polymers such as polyacetylene and polypyrrole, and oxides such as SnO ₂ can be used.

  In addition, various types of metals can be used as materials capable of alloying lithium, but tin (Sn), cobalt (Co), indium (In), Al, silicon (Si), and alloys thereof can be used. Often used. When metallic lithium is used, it is not always necessary to use powder as a coating film with a binder, and a method of pressure bonding a rolled lithium metal foil to a current collector may be used.

  As the binder, for example, polyvinylidene fluoride, styrene butadiene rubber or the like is used. Moreover, as a solvent, N-methylpyrrolidone, methyl ethyl ketone, etc. are used, for example.

  The above-described negative electrode active material, binder, and conductive agent are uniformly mixed to form a negative electrode mixture, which is dispersed in a solvent to form a slurry. Subsequently, after apply | coating uniformly on a negative electrode electrical power collector by the method similar to a positive electrode, the negative electrode active material layer 12b is formed by making it dry at high temperature and flying a solvent.

  Similarly to the positive electrode 21, the negative electrode 22 has a negative electrode terminal 21b connected to one end of the negative electrode current collector by spot welding or ultrasonic welding, and the negative electrode terminal 21b is electrochemically and chemically stable. There is no problem even if it is not metal as long as it can conduct electricity. Examples of the material of the negative electrode terminal 21b include copper and nickel.

  The positive electrode terminal 21a and the negative electrode terminal 21b are preferably derived from the same direction, but there is no problem even if they are derived from any direction as long as no short circuit or the like occurs and there is no problem in battery performance. Moreover, the connection location of the positive electrode terminal 21a and the negative electrode terminal 21b is not limited to the above-described example as long as electrical contact is established.

[Electrolyte]
As the electrolytic solution, an electrolyte salt and an organic solvent that are generally used in lithium ion batteries can be used.

  Specific examples of the non-aqueous solvent include ethylene carbonate, propylene carbonate, γ-butyrolactone, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, dipropyl carbonate, ethyl propyl carbonate, or hydrogen of these carbonic acid esters to halogen. Examples include substituted solvents. One of these solvents may be used alone, or a plurality of these solvents may be mixed with a predetermined composition.

Moreover, as lithium salt, it is possible to use the material used for normal battery electrolyte solution. Specifically, LiCl, LiBr, LiI, LiClO ₃ , LiClO ₄ , LiBF ₄ , LiPF ₆ , LiNO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiAsF ₆ , LiCF ₃ SO ₃ , LiC (SO ₂ CF ₃ ) ₃ , LiAlCl ₄ , LiSiF _{6 and the} like can be mentioned, but LiPF ₆ and LiBF ₄ are preferable from the viewpoint of oxidation stability. These lithium salts may be used alone or in combination of two or more. There is no problem as long as the lithium salt can be dissolved in the above solvent, but the lithium ion concentration is 0.4 mol / kg or more and 2.0 mol / kg or less with respect to the non-aqueous solvent. Preferably there is.

  When a polymer electrolyte is used, the above-described electrolyte is gelled with a matrix polymer. The matrix polymer is not particularly limited as long as it is compatible with a non-aqueous electrolyte obtained by dissolving the electrolyte salt in the non-aqueous solvent and can be gelled. Examples of such a matrix polymer include a polymer containing polyvinylidene fluoride, polyethylene oxide, polypropylene oxide, polyacrylonitrile, and polymethacrylonitrile in repeating units. Such a polymer may be used individually by 1 type, and may mix and use 2 or more types.

Among them, particularly preferred as the matrix polymer is polyvinylidene fluoride or a copolymer in which hexafluoropropylene is introduced at a ratio of 7.5% or less to polyvinylidene fluoride. Such polymers have a number average molecular weight in the range of 5.0 × 10 ⁵ to 7.0 × 10 ⁵ (500,000 to 700,000) or a weight average molecular weight of 2.1 × 10 ⁵ to 3. The range is 1 × 10 ⁵ (210,000-310,000), and the intrinsic viscosity is in the range of 1.7 to 2.1.

[Separator]
The separator 23 is made of a porous film made of a polyolefin-based material such as polypropylene (PP) or polyethylene (PE), or a porous film made of an inorganic material such as a ceramic nonwoven fabric. The separator 23 may have a structure in which two or more kinds of porous films are laminated. Among these, polyethylene and polypropylene porous films are the most effective.

  In general, the thickness of the separator 23 is preferably 5 to 50 μm, more preferably 7 to 30 μm. When the separator 23 is too thick, the active material filling amount is reduced, the battery capacity is reduced, the ionic conductivity is lowered, and the current characteristics are lowered. On the other hand, if the film is too thin, the mechanical strength of the film decreases.

[Laminate film]
As shown in the cross-sectional view of FIG. 9, the laminate film 23 is a multilayer film in which a film-like metal and a synthetic resin are bonded together. The laminate film 23 has, for example, a configuration in which a heat-fusible layer 23a, a metal layer 23b, and a surface protective layer 23c are laminated in order from the inner side in contact with the battery element.

  The heat sealing layer 23a has a function of performing heat welding and a function of preventing deterioration of the polymer electrolyte. For example, polypropylene, polyethylene, or the like is used. As the polypropylene, non-axially stretched polypropylene (CPP) or the like is used, and as the polyethylene, non-axially stretched low density polyethylene (LLDPE) or the like is used. The resin material constituting the heat-sealing layer 23a has a melting point such that the battery element 20 is not affected by the heat applied to the battery element 20 during heat-sealing.

  The metal layer 23b has a function of preventing moisture from entering the inside, and for example, an aluminum (Al) foil is used. As aluminum, for example, 3003H18, 3004H18, 1N30H18, or the like can be used.

  The surface protective layer 23c has a function of insulating the aluminum layer and the battery cell 20, and for example, nylon (Ny) or polyethylene terephthalate (PET) is used.

  In the laminate film 23, polypropylene, polyethylene or the like is used as the heat-sealing layer 23a, and nylon (Ny) or polyethylene terephthalate (PET) having a melting point higher than that of polypropylene, polyethylene or the like is used as the surface protective layer 23c. Thereby, since the heat sealing | fusion layer 23a fuse | melts before the surface protective layer 23c, when sealing a laminate film by heat sealing | fusion, it can join easily.

  Such a laminate film 23 is appropriately sized according to the shape of the battery element 20, and the battery element accommodating portion 24 is formed. The battery element housing portion 24 is formed by, for example, deep drawing from the heat-fusible layer 23a side to the surface protective layer 23c side.

(1-2) Production of non-aqueous electrolyte battery [Production of positive electrode]
The above-described positive electrode active material, binder, and conductive agent are uniformly mixed to form a positive electrode mixture, and this positive electrode mixture is dispersed in a solvent to form a slurry. Here, the positive electrode active material, the conductive agent, and the binder need only be uniformly dispersed, and the mixing ratio is not limited. Next, the slurry is uniformly applied on the positive electrode current collector by a doctor blade method or the like, and then compressed and dried by a high-temperature roll press machine or the like to drive off the solvent, thereby forming a positive electrode active material layer. In addition, as a solvent, N-methylpyrrolidone etc. are used, for example.

[Production of negative electrode]
These are uniformly mixed to form a negative electrode mixture, and this negative electrode mixture is dispersed in a solvent to form a slurry. Next, the slurry is uniformly applied on the negative electrode current collector by a doctor blade method or the like, and compressed and dried by a high-temperature roll press machine or the like to drive off the solvent, thereby forming a negative electrode active material layer. Here, the mixing ratio of the negative electrode active material, the conductive agent, the binder, and the solvent is not limited as in the positive electrode active material.

[Production of battery element]
The positive electrode and the negative electrode produced as described above are stacked in the order of the positive electrode, the separator, the negative electrode, and the separator and wound to obtain the battery element 20. Here, when using a polymer electrolyte instead of the electrolyte solution, first, a gel electrolyte solution is uniformly applied to the positive electrode and the negative electrode. Then, after impregnating the positive electrode active material layer and the negative electrode active material layer with the electrolyte solution, the positive electrode active material layer and the negative electrode active material layer are stored at room temperature, or a polymer electrolyte layer is formed on the positive electrode active material layer and the negative electrode active material layer through a drying process.

  Subsequently, a sealant 22a and a sealant 22b made of, for example, a rectangular resin film are bonded in advance to both surfaces of the positive electrode terminal 21a and the negative electrode terminal 21b derived from the battery element 20.

[Exterior by laminate film]
A process of covering the battery element 20 with the laminate film 23 will be described with reference to FIGS.

  First, as shown in FIG. 10A, the electronic element 20 is accommodated in the battery element accommodating portion 24 formed on the laminate film 23 and is packaged.

  Next, as shown in FIG. 10B, one side part is sealed. The side portion is sealed with a flat heater block without a cutout portion. Subsequently, the top portion is sealed. The step of sealing the top portion will be described in detail with reference to FIGS. 11A to 11C.

  First, as shown in FIG. 11A, the laminate film 23 is disposed so as to sandwich the positive electrode terminal 21a provided with the sealant 22a and the negative electrode terminal 21b provided with the sealant 22b from above and below. Then, as shown in FIG. 11B, the top portion is sealed using the first heater block 41. At this time, the temperature of the first heater block is higher than the melting point of the resin material constituting the heat-sealing layer 23a of the laminate film 23 and lower than the melting point of the resin material constituting the surface protective layer 23c.

  The first heater block 41 includes, for example, an upper heater block 41 having notch widths 41a and 41b that are approximately 2 mm wider than the width of the sealants 22a and 22b, and a flat lower heater block 42. The lower heater block 42 may have the same shape as the upper heater block 41. As shown in FIG. 11C, a gap may be generated between the sealants 22 a and 22 b and the laminate film 23 at the time after sealing with the first heater block 41.

  Subsequently, as shown in FIG. 10C, the top portion is sealed again. The process of sealing the top part again will be described in detail with reference to FIGS. 11D to 11F. FIG. 12 shows a process of detecting the positions of the positive electrode terminal 21a and the negative electrode terminal 21b in order to determine the position of the second heater block when the top portion is sealed again.

  After the top portion is sealed by the first heater block, the positions of the positive electrode terminal 21a and the negative electrode terminal 21b are detected using the sensor 60 as shown in FIG. As the sensor 60, for example, a laser sensor can be used. The sensor 60 includes a light emitting unit 60a and a light receiving unit 60b, and the light emitted from the light emitting unit 60a is received by the light receiving unit 60b. At the position of the positive electrode terminal 21a or the negative electrode terminal 21b, the laser from the light emitting unit 60a is blocked by the positive electrode terminal 21a or the negative electrode terminal 21 and is not received by the light receiving unit 60b. In the sensor 60, detection is performed on the assumption that the positive electrode terminal 21a or the negative electrode terminal 21b is located in a portion where the light receiving unit 60b does not receive the laser.

  For example, as shown in FIG. 12, when the position of the positive electrode terminal 21a and the negative electrode terminal 21b is detected by moving the sensor 60 from the positive electrode terminal 21a side to the negative electrode terminal 21b side, Only one end needs to be detected. The widths of the positive terminal 21a and the negative terminal 21b are determined in advance. For this reason, the position of both ends of the positive electrode terminal 21a and the negative electrode terminal 21b can be obtained only by detecting the position where the light receiving unit stops receiving the laser beam. Of course, the positions at which both ends of the positive terminal 21a and the negative terminal 21b may be obtained by detecting the position where the light receiving section stops receiving the laser and the position where the light receiving section resumes receiving the laser.

  After the positions of the positive electrode terminal 21a and the negative electrode terminal 21b are detected using the sensor 60, the top portion is resealed by the second heater block as shown in FIG. 10C. FIG. 10C shows in detail the portion indicated by the dotted line in FIG. 10B. The step of resealing the top portion will be described in detail with reference to FIGS. 11D to 11F.

  In re-sealing the top portion, as shown in FIG. 11D, for example, a second heater block 50 having cutout portions 51a and 51b having a narrower width than the widths of the sealants 22a and 22b is used. Then, the top portion is sealed using the second heater block 50 as shown in FIG. 11E. At this time, the second heater block 50 is set to a temperature that is higher than the melting point of the resin material and the sealant 22 constituting the heat-sealing layer 23a of the laminate film 23 and lower than the melting point of the resin material constituting the surface protective layer 23c. The

  The second heater block includes, for example, an upper heater block 51 having notches 51a and 51b having a width slightly narrower than the width of the sealants 22a and 22b, and a flat lower heater block 52. The lower heater block 52 may have the same shape as the upper heater block 51. When the lower heater block 42 and the lower heater block 52 have a flat shape, the lower heater block 42 and the lower heater block 52 may be the same. As shown in FIG. 11F, by sealing with the second heater block 50, the first and second step portions are provided so that no gap is generated between the sealant 22 and the laminate film 23. Sealing can be performed.

  When re-sealing the top portion, if the pressing force of the second heater block is too strong, the molten resin in the portion of the heat-sealing layer facing the second heater block is pushed out more than necessary. End up. Thereby, the resin layer of the part pressed by the 2nd heater block will become thin too much, and the problem that sealing performance will fall arises.

  Further, as shown in FIG. 13, the resin melted by the pressing of the second heater block is forcibly pushed out, particularly in the portion already sealed by the first heater block.

  For this reason, in the nonaqueous electrolyte battery 30, as described above, the step thickness T2 is preferably 105% or more of the sealing portion thickness T1, and the step thickness T2 is equal to the notch portion thickness T3. On the other hand, it is preferable to have a thickness of 90% or less.

  By forming the first step portion and the second step portion having such a thickness, the end portion of the sealant 22 does not come into contact with the top portion of the non-aqueous electrolyte battery 30 as shown in FIG. Sealability can be improved.

  When resealing the top portion with the second heater block 50, the first step portion 25 and the second step portion 26 are formed with the above-described thicknesses, so that sealing is performed with an appropriate pressure. There is a need to do. For example, the second heater block 50 preferably seals the top portion with a pressure of about 0.10 MPa or more and 0.20 MPa or less. When the pressure at the time of sealing is too weak, the step thickness T2 is increased, and the gap between the sealant 22 and the laminate film 23 remains or the sealing width is too narrow, resulting in a decrease in sealing performance. . Moreover, when the pressure at the time of sealing is too strong, level | step difference thickness T2 will become thin, a resin layer will become thin too much or the sealant 22 will bend, and sealing performance will fall.

  Then, as shown to FIG. 10D, electrolyte solution is inject | poured from opening of one side part which is not sealed. And the non-aqueous electrolyte battery 30 as shown to FIG. 10F can be obtained by sealing the one side which is not sealed in a pressure-reduced environment, and folding the laminate film 23 extended from a side part.

  In the nonaqueous electrolyte battery 30 of the present invention, after sealing the portion except for the vicinity of the electrode terminal 21 with certainty, the vicinity of the electrode terminal 21 is resealed. At this time, sealing performance can be improved by performing resealing so that the first step portion 25 and the second step portion 26 are provided. Thus, it is possible to prevent moisture from entering the battery and leakage of the electrolyte without using a wide sealant that easily interferes with a circuit board or the like. For example, even when the pressure inside the battery is increased, the sealing portion is unlikely to open and safety can be improved.

<Example 1>
In Example 1 below, the non-aqueous electrolyte battery in which the top portion was sealed using the first heater block and the second heater block having notches having different widths was produced, respectively, and sealing performance was improved. confirmed.

<Example 1-1>
[Production of positive electrode]
92% by weight of lithium cobaltate (LiCoO ₂ ), 3% by weight of powdered polyvinylidene fluoride, and 5% by weight of powdered graphite were uniformly mixed and dispersed in N-methylpyrrolidone to form a slurry-like positive electrode composite. An agent was prepared. This positive electrode mixture was uniformly applied on both surfaces of an aluminum foil serving as a positive electrode current collector, and dried under reduced pressure at 100 ° C. for 24 hours to form a positive electrode active material layer.

  Next, this was pressure-formed by a roll press machine to obtain a positive electrode sheet, the positive electrode sheet was cut into a strip shape to be a positive electrode, and a positive electrode terminal made of an aluminum foil having a width of 4 mm was welded to an uncoated portion of the active material. Further, a sealant made of a polypropylene resin film having a width of 6 mm was adhered to a portion of the positive electrode terminal facing the heat-sealing layer when being covered with a laminate film.

[Production of negative electrode]
Artificial graphite (91% by weight) and powdery polyvinylidene fluoride (9% by weight) were uniformly mixed and dispersed in N-methylpyrrolidone to prepare a slurry-like negative electrode mixture. Next, this negative electrode mixture was uniformly applied to both surfaces of a copper foil serving as a negative electrode current collector, and dried under reduced pressure at 120 ° C. for 24 hours to form a negative electrode active material layer.

  Next, this was pressure-formed by a roll press machine to obtain a negative electrode sheet, the negative electrode sheet was cut into a strip shape to form a negative electrode, and a negative electrode terminal made of nickel foil having a width of 4 mm was welded to the uncoated portion of the substance. Further, a sealant made of a polypropylene resin film having a width of 6 mm was bonded to a portion of the negative electrode terminal facing the heat-sealing layer when being covered with a laminate film.

[Preparation of electrolyte]
Ethylene carbonate (EC) and propylene carbonate (PC) were mixed at a weight ratio of 6: 4, and 0.8 mol / kg LiPF ₆ and 0.2 mol / kg LiBF ₄ were dissolved to prepare a banquet liquid.

[Production of battery element]
A battery element was obtained by winding a belt-like positive electrode and a belt-like negative electrode in the longitudinal direction through a belt-like separator to obtain a flat shape. As the separator, a porous polyethylene film having a thickness of 10 μm was used.

[Preparation of non-aqueous electrolyte battery]
Next, using the laminate film in which the battery element accommodating portion was formed by deep drawing, the electronic element was accommodated in the battery element accommodating portion, and the laminate film was folded and packaged so as to cover the opening of the battery element accommodating portion. At this time, the laminate was heat-sealed so that the sealant bonded to the positive electrode terminal and the negative electrode terminal was sandwiched between the heat-sealing layers of the laminate film.

  Thereafter, one side of the side portion was heat-sealed with a heater block. Subsequently, using the first heater block having a notch with a width of 8 mm, the battery element lead-out side was heat-sealed so as to avoid the positive electrode terminal lead-out part and the negative electrode terminal lead-out part. Subsequently, the positions of the positive electrode terminal and the negative electrode terminal were detected by a laser sensor. Then, using a second heater block having a notch portion having a width of 7 mm, the battery element lead-out side was heat-sealed so as to avoid the positive electrode terminal lead-out portion and the negative electrode terminal lead-out portion.

  At this time, the first step portion and the second step portion are formed. The thickness of the sealing portion on the battery element lead-out side (sealing portion thickness T1 shown in FIG. 5) was 150 μm. The thickness of the first step portion (step thickness T2 shown in FIG. 5) was 210 μm, and the thickness of the second step portion (notch portion thickness T3 shown in FIG. 5) was 320 μm. That is, the thickness of the first step portion was 140% with respect to the sealing portion and 66% with respect to the second step portion. The length of the second step portion in the electrode terminal lead-out direction was equal to the length of the sealing portion and was 1.5 mm.

  Finally, after pouring electrolyte solution from the opening of the laminate film, the remaining one side was heat-sealed and sealed to produce a non-aqueous electrolyte battery.

<Example 1-2>
A nonaqueous electrolyte battery was produced in the same manner as in Example 1-1 except that the notch width of the second heater block was changed to 6 mm.

<Example 1-3>
A nonaqueous electrolyte battery was produced in the same manner as in Example 1-1 except that the notch width of the second heater block was changed to 5 mm.

<Example 1-4>
A nonaqueous electrolyte battery was produced in the same manner as in Example 1-1 except that the notch width of the second heater block was set to 7.6 mm.

<Comparative Example 1-1>
A nonaqueous electrolyte battery was produced in the same manner as in Example 1-1 except that the second heater block was not resealed.

<Comparative Example 1-2>
A nonaqueous electrolyte battery was produced in the same manner as in Example 1-1 except that the cutout width of the first heater block was 5 mm and re-sealing with the second heater block was not performed.

<Comparative Example 1-3>
A nonaqueous electrolyte battery was produced in the same manner as in Example 1-1 except that the notch width of the second heater block was 7.8 mm.

[Measurement of cleavage pressure]
For Examples 1-1 to 1-4 and Comparative Examples 1-1 to 1-3 described above, gas was forcibly sent into the laminate film covering the battery element, and the sealing portion of the electrode terminal lead-out portion was cleaved. When the pressure was measured. In addition, each Example and Comparative Example 15 were produced, respectively, and the average value and standard deviation of the cleavage pressure were determined.

  Table 1 below shows the measurement results.

  As shown in Table 1, in Examples 1-1 to 1-4, the first heater block having a notch width slightly wider than the sealant width, and narrower than the first heater block and wider than the width of the electrode terminal. A second heater block having a notch width was used. Here, the second heater block is narrower than the first heater block by a distance corresponding to 20% of the difference between the width of the first heater block and the width of the sealant (that is, 0.4 mm). In Examples 1-1 to 1-4 as described above, it was found that the average value of the cleavage pressure was as high as over 0.4 MPa, and the sealing performance was high. In addition, the standard deviation of the cleavage pressure was small and the variation in the cleavage pressure was small, that is, the non-aqueous electrolyte battery having high sealing performance without any variation in sealing performance could be stably produced.

  On the other hand, in Comparative Examples 1-1 and 1-2, re-sealing by the second heater block was not performed. In the comparative example 1, it turned out that the average value of cleavage pressure becomes low and sealing performance falls. In Comparative Example 2 using the first heater block with a narrow notch width, the average value of the cleavage pressure was not as low as in Comparative Example 1, but the standard deviation of the cleavage pressure was in each Example and Comparative Example 1. It became higher than. This is considered that the sealing state is likely to vary, such as deformation due to the sealant during sealing with the first heater block. Furthermore, in Comparative Example 1-3, a second heater block (less than a distance corresponding to 20% of the difference between the width of the first heater block and the width of the sealant (that is, 0.4 mm) and narrower than the first heater block) A notch width of 7.8 mm) was used. In Comparative Example 1-3, the cleavage pressure was approximately the same as that of Comparative Example 1-1 in which the second heater block was not used, and the notch width of the first heater block and the notch width of the second heater block It was found that the effect is difficult to obtain when is too close.

  Comparing Example 1-3 and Comparative Example 1-2, both use a heater block with a notch width of 5 mm. However, it was found that sealing can be performed appropriately by providing a step portion at the electrode terminal lead-out portion and sealing the top portion.

<Example 2>
In Example 2 below, non-aqueous electrolyte batteries in which first step portions having different thicknesses were formed were manufactured, and sealing properties were confirmed.

<Example 2-1>
A nonaqueous electrolyte battery was fabricated in the same manner as in Example 1-1 except that the notch width of the second heater block was 5 mm and the thickness of the first step portion was 160 μm. Here, the thickness of the sealing part in Example 2-1 is 150 μm, and the thickness of the second stepped part is 320 μm, which is the same as in Example 1. In Example 2-1, the first step portion is 107% with respect to the thickness of the sealing portion and 50% with respect to the thickness of the second step portion.

<Example 2-2>
Example 2-1 except that the thickness of the first step portion is 210 μm, that is, the first step portion is 140% with respect to the thickness of the sealing portion and 66% with respect to the thickness of the second step portion. A nonaqueous electrolyte battery was produced in the same manner as described above.

<Example 2-3>
Example 2-1 except that the thickness of the first step portion was 280 μm, that is, the first step portion was 187% with respect to the thickness of the sealing portion and 88% with respect to the thickness of the second step portion. A nonaqueous electrolyte battery was produced in the same manner as described above.

<Comparative Example 2-1>
Example 2-1 except that the thickness of the first step portion is 155 μm, that is, the first step portion is 103% with respect to the thickness of the sealing portion and 48% with respect to the thickness of the second step portion. A nonaqueous electrolyte battery was produced in the same manner as described above. In addition, Comparative Example 2-1 is a nonaqueous electrolyte battery in which the first stepped portion is largely crushed.

<Comparative Example 2-2>
Example 2-1 except that the thickness of the first stepped portion was 290 μm, that is, the first stepped portion was 193% with respect to the thickness of the sealing portion and 91% with respect to the thickness of the second stepped portion. A nonaqueous electrolyte battery was produced in the same manner as described above. In addition, Comparative Example 2-2 is a nonaqueous electrolyte battery in which the first stepped portion is not crushed.

<Comparative Example 2-3>
Example 2-1 except that the thickness of the first stepped portion is 150 μm, that is, the first stepped portion is 100% with respect to the thickness of the sealing portion and 47% with respect to the thickness of the second stepped portion. A nonaqueous electrolyte battery was produced in the same manner as described above. In addition, Comparative Example 2-3 is a non-aqueous electrolyte battery in which the first step portion is largely crushed and has a thickness equivalent to that of the sealing portion.

<Comparative Example 2-4>
Example 2-1 except that the thickness of the first step portion is 320 μm, that is, the first step portion is 213% with respect to the thickness of the sealing portion and 100% with respect to the thickness of the second step portion. A nonaqueous electrolyte battery was produced in the same manner as described above. In addition, Comparative Example 2-4 is a nonaqueous electrolyte battery in which the first stepped portion is less crushed and has the same thickness as the second stepped portion.

[Measurement of cleavage pressure]
For Examples 2-1 to 2-3 and Comparative Examples 2-1 to 2-4 described above, the pressure when the sealing portion of the electrode terminal lead-out portion was cleaved was measured by the same method as in Example 1. In addition, each Example and Comparative Example 15 were produced, respectively, and the average value and standard deviation of the cleavage pressure were determined.

  Table 2 below shows the measurement results.

  As shown in Table 2, in Examples 2-1 to 2-3, the average value of the cleavage pressure was as high as more than 0.4 MPa, and it was found that the sealing performance was high. In addition, the standard deviation of the cleavage pressure was small and the variation in the cleavage pressure was small, that is, the non-aqueous electrolyte battery having high sealing performance without any variation in sealing performance could be stably produced.

  On the other hand, as can be seen from Comparative Examples 2 to 2-4, when the thickness of the first step portion is equal to or close to the thickness of the sealing portion, or the thickness of the first step portion is the second step. When the thickness was equal to or close to the thickness of the part, the cleavage pressure was reduced as compared with each example. In Comparative Examples 2-1 and 2-3 in which the thickness of the first step portion is equal to or close to the thickness of the sealing portion, the standard deviation of the cleavage pressure is large and the variation in the cleavage pressure is large. It was found that there was variation.

<Example 3>
In Example 3 below, non-aqueous electrolyte batteries each having a second step portion having a different length in the electrode terminal lead-out direction were produced, and the sealing performance was confirmed.

<Example 3-1>
The same as in Example 1-1 except that the cutout width of the second heater block is 5 mm, the length of the sealing portion is 1.5 mm, and the length of the second stepped portion is 0.3 mm. A water electrolyte battery was prepared. Here, the thickness of the sealing portion in Example 2-1 is 150 μm, the thickness of the first stepped portion is 210 μm, and the thickness of the second stepped portion is 320 μm, which is the same as in Example 1.

<Example 3-2>
A nonaqueous electrolyte battery was produced in the same manner as in Example 3-1, except that the length of the second step portion was 0.9 mm.

<Example 3-3>
A nonaqueous electrolyte battery was produced in the same manner as in Example 3-1, except that the length of the second stepped portion was 1.5 mm, which was the same as the length of the sealing portion.

<Comparative Example 3-1>
A nonaqueous electrolyte battery was produced in the same manner as in Example 3-1, except that the length of the second step portion was 0 mm, that is, the second step portion was not provided.

[Measurement of cleavage pressure]
About the above-mentioned Example 3-1 thru | or 3-3 and Comparative Example 3-1, the pressure when the sealing part of an electrode terminal derivation | leading part cleaved by the method similar to Example 1 was measured. In addition, each Example and Comparative Example 15 were produced, respectively, and the average value and standard deviation of the cleavage pressure were determined.

  Table 3 below shows the measurement results.

As shown in Table 2, in Examples 2-1 to 2-3, the average value of the cleavage pressure was as high as more than 0.4 MPa, and it was found that the sealing performance was high. In addition, the standard deviation of the cleavage pressure was small and the variation in the cleavage pressure was small, that is, the non-aqueous electrolyte battery having high sealing performance without any variation in sealing performance could be stably produced. And it turned out that sealing property becomes high, so that the length of the 2nd level | step-difference part is long, ie, it is close to the length of a sealing part.

  On the other hand, in Comparative Example 3-1, it was found that the second stepped portion was not formed and the gap was not filled, so that the cleavage pressure was lower than in each Example.

  As can be seen from Examples 1 to 3, the width, thickness, and length of the first step portion and the second step portion formed in the electrode terminal lead-out portion of the nonaqueous electrolyte battery are appropriately set. Thus, it is possible to obtain a nonaqueous electrolyte battery having a stable and high sealing property.

  As mentioned above, although embodiment of this invention was described concretely, this invention is not limited to the above-mentioned embodiment, The various deformation | transformation based on the technical idea of this invention is possible.

  For example, the numerical values given in the above embodiment are merely examples, and different numerical values may be used as necessary.

  Moreover, although the example using a wound-type battery element was demonstrated in the above-mentioned embodiment, it is not restricted to this. The present invention can be applied to a non-aqueous electrolyte battery in which a battery element is packaged with a laminate film, and the battery element can use other configurations such as a laminated type.

  Further, different methods may be used to detect the lead-out positions of the positive electrode terminal and the negative electrode terminal.

DESCRIPTION OF SYMBOLS 1,21 ... Electrode terminal 1a, 21a ... Positive electrode terminal 1b, 21b ... Negative electrode terminal 2, 2a, 2b, 22, 22a, 22b ... Sealant 3,23 ... Laminate film 3a, 23a ... heat-sealing layers 3b, 23b ... metal layers 3c, 23c ... surface protective layers 10, 41, 42 ... heater blocks 10a, 10b ... notches 20 ... battery elements 24 ... Battery element housing part 25 ...
26 ...
30 ... Non-aqueous electrolyte battery

Claims (10)

A battery element having a positive electrode, a negative electrode, a positive electrode terminal connected to the positive electrode, and a negative electrode terminal connected to the negative electrode;
A non-aqueous electrolyte,
A metal layer; a surface protective layer made of a first resin material formed on one surface of the metal layer; and a heat-sealing layer made of a second resin material formed on the other surface of the metal layer. And an exterior material in which a recess is formed from the heat-sealable layer side toward the surface protective layer side,
A sealing member is provided on a portion of the positive electrode terminal and the negative electrode terminal facing the exterior material,
The battery element is housed in the recess, the battery element is sheathed by the exterior material, and the positive electrode terminal and the negative electrode terminal are sandwiched between the heat-sealing layers of the exterior material through the sealing member. Led out of the exterior material,
The lead portion of the positive terminal and the negative terminal is provided with a first step portion and a second step portion,
The thickness of the first step portion is 105% or more with respect to the thickness of the sealing portion other than the positive electrode terminal and the lead-out portion of the negative electrode terminal and 90% or less with respect to the thickness of the second step portion,
The length of the positive terminal and the negative terminal lead-out direction of the first step portion and the second step portion is 0.3 mm or more and not more than the length of the sealing portion,
The width of the second step portion is wider than the width of the positive terminal and the negative terminal, and 20% or more of the difference between the width of the first step portion and the width of the sealing member, A non-aqueous electrolyte battery that is narrower than the width of the step. 2. The nonaqueous electrolyte battery according to claim 1, wherein a width of the second stepped portion is wider than a width of the positive electrode terminal and the negative electrode terminal and equal to or smaller than a width of the sealing member. The nonaqueous electrolyte battery according to claim 2, wherein the length of the positive electrode terminal and the negative electrode terminal in the second stepped portion is equal to the length of the first stepped portion. The nonaqueous electrolyte battery according to claim 1, wherein the melting point of the second resin material is lower than the melting point of the first resin material. A battery element having a positive electrode, a negative electrode, a positive electrode terminal connected to the positive electrode, and a negative electrode terminal connected to the negative electrode, wherein a sealing member is provided on a part of the positive electrode terminal and the negative electrode terminal. A metal layer, a surface protective layer made of a first resin material formed on one surface of the metal layer, and a heat fusion layer made of a second resin material formed on the other surface of the metal layer. And having the positive electrode terminal and the negative electrode terminal pass through the sealing member through the sealing member. A step of exterior to be sandwiched between layers,
A first sealing step of heat-sealing at least one side excluding one side other than the electrode terminal lead-out side and the electrode terminal lead-out side from which the positive electrode terminal and the negative electrode terminal are derived;
By the first heater block having a first notch and a second notch having a width wider than the width of the sealing member, the first notch and the second notch are A second sealing step of thermally fusing the electrode terminal lead-out side so as to face the positive electrode terminal and the negative electrode terminal,
More than 20% of the difference between the widths of the positive electrode terminal and the negative electrode terminal and the width of the first notch and the second notch and the width of the sealing member. And a second heater block having a third cutout portion and a fourth cutout portion that are narrower than the width of the second cutout portion, and the third cutout portion and the fourth cutout portion. By heat-sealing the electrode terminal lead-out side so that the notch faces the positive electrode terminal and the negative electrode terminal, the first and second stepped portions are formed in the lead-out part of the positive electrode terminal and the negative electrode terminal. A third sealing step to form;
A non-aqueous electrolyte battery manufacturing method comprising: a fourth sealing step of heat-sealing one side that is not sealed other than the electrode terminal lead-out side. In the third sealing step, the thickness of the first stepped portion is 105% or more with respect to the thickness of the sealing portion other than the positive electrode terminal and the lead-out portion of the negative electrode terminal, and the second stepped portion The method for producing a nonaqueous electrolyte battery according to claim 5, wherein the nonaqueous electrolyte battery is formed so as to have a thickness of 90% or less. In the third sealing step, a second heater having a third notch and a fourth notch that are wider than the positive terminal and the negative terminal and narrower than the sealing member. The method for manufacturing a nonaqueous electrolyte battery according to claim 6, wherein the first and second step portions are formed by blocks. The method for producing a nonaqueous electrolyte battery according to claim 7, wherein temperatures of the first heater block and the second heater block are equal to or higher than a melting point of the heat sealing layer and lower than a melting point of the surface protective layer. After the second sealing step, there is a detection step of detecting the positions of the positive terminal and the negative terminal,
In the third step, the second heater is arranged such that the third notch portion and the fourth notch portion face the positions of the positive electrode terminal and the negative electrode terminal detected in the detection step. The method for producing a nonaqueous electrolyte battery according to claim 8, wherein the block is positioned. 9. The nonaqueous electrolyte battery according to claim 8, further comprising a step of injecting the electrolyte into the exterior material after the third sealing step when an electrolyte is used as the nonaqueous electrolyte. Manufacturing method.

Images