JP6506576B2 - battery - Google Patents

Description

  The present invention relates to a battery.

  BACKGROUND In recent years, portable devices with relatively large power consumption, such as smartphones and tablets with large screens, have been in widespread use. Along with this, the demand for increasing the capacity and size of the battery is increasing.

  A battery with a large capacity or a large size receives a large impact when dropped. For example, when the battery falls from the corner, there is a possibility that the battery case which also functions as a positive electrode terminal and the negative electrode of the electrode body accommodated in the battery case may be in contact and short circuited. For this reason, it is preferable that the side surfaces on the bottom and bottom sides of the electrode body be completely covered with an insulating tape or the like.

  There is known a battery having a configuration in which the bottom of an electrode body having a positive electrode and a negative electrode is covered with an insulating tape, and the electrode body is accommodated in an outer can. In Patent Document 1, a rectangular insulating tape which is slightly larger than the bottom surface of the rectangular electrode body is attached to the bottom surface of the electrode body, and the remaining portion of the insulating tape is broken to be attached also to the bottom side of the side surface of the electrode body. Is disclosed.

JP 2012-33419 A

  However, when using a rectangular insulating tape and attaching it to the bottom of the electrode body and the bottom side of the side, the bottom of the electrode body, the first side, and the second side are attached in this order. It becomes difficult to stick so as to completely cover the side surface of the battery, and there is a possibility that the positive electrode and the negative electrode may short circuit when the battery is dropped. In this case, if the second side surface of the electrode body is to be pasted so as to completely cover the insulating tape, the step of pasting the insulating tape becomes complicated.

  The present invention completely covers not only the bottom surface of the electrode body and the bottom surface of the first side surface but also the bottom surface side of the second side surface with an insulator, and the occurrence of contact between the positive electrode and the negative electrode of the electrode body when dropped An object is to provide a battery that can be suppressed.

  A battery according to an embodiment of the present invention includes an electrode body, a battery case, and an insulator. The electrode body has a flat shape including a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode. The battery case accommodates the electrode body. The insulator has a first insulating portion covering the bottom of the electrode body and the bottom of the first side, and a second insulating portion covering the bottom of the second side narrower than the first side. And the body. The first insulating portion and the second insulating portion are not connected on the side surface of the electrode body (first configuration).

  According to the first configuration, the insulator has a separated shape in which the first insulating portion and the second insulating portion are not connected on the side surface of the electrode body. Thus, not only the bottom side of the first side surface of the electrode body but also the bottom side of the second side surface can be completely covered, thereby suppressing the occurrence of contact between the positive electrode and the negative electrode of the electrode body when dropped. be able to.

  In the state where the insulator is developed, the second insulating portion may be provided on both outer sides in one direction of the first insulating portion (second configuration).

  According to the second configuration, after the bottom surface of the electrode body and the bottom surface side of the first side surface are covered with the first insulating portion, the electrode body is formed by the second insulating portions provided on both outer sides of the first insulating portion Can completely cover the bottom side of the second side. Thereby, the occurrence of the contact between the positive electrode and the negative electrode of the electrode body at the time of drop can be suppressed.

  The insulator may be cut into four parts, and the cut may divide the insulator into a first insulating portion and a second insulating portion (third configuration).

  According to the third configuration, since the first insulating portion and the second insulating portion can be divided only by cutting four parts of one insulator, the bottom surface side of the second side surface of the electrode body is An insulator that can be completely covered can be easily manufactured.

  The battery case may have an opening on the upper surface side opposite to the bottom surface of the electrode body (fourth configuration).

  According to the fourth configuration, the insulator is inserted by inserting the electrode body from the opening of the battery case while the bottom surface of the electrode body and the bottom side of the first side surface are covered with the first insulating portion of the insulator The second insulating portion of the second embodiment can be naturally folded to completely cover the second side of the electrode body.

  According to the battery of the present disclosure, not only the bottom of the electrode body and the bottom of the first side but also the bottom of the second side can be completely covered by the insulator, and the positive electrode of the electrode when dropped It is possible to suppress the occurrence of contact between the electrode and the negative electrode.

FIG. 1 is a perspective view showing an outline of a battery according to Embodiment 1. FIG. FIG. 2 is a cross-sectional view of the battery shown in FIG. 1 taken along the line II-II. FIG. 3 is a development view of the insulating tape used in the battery according to the first embodiment. FIG. 4 is a view showing a state in which the first insulating portion of the insulating tape is attached to the bottom surface of the electrode body and the bottom surface of the first side surface in the battery according to the first embodiment. FIG. 5 shows how the electrode body is inserted into the battery case with the first insulating portion of the insulating tape attached to the bottom surface of the electrode body and the bottom surface of the first side in the battery according to Embodiment 1. FIG. FIG. 6 is a view showing a first side surface of the electrode body when the electrode body is completely inserted into the battery case in the battery according to the first embodiment. FIG. 7 is a view showing a second side surface of the electrode body when the insertion of the electrode body into the battery case is completed in the battery according to Embodiment 1. FIG. 8 is a view showing how a rectangular insulating tape is attached to the bottom surface and the bottom surface side of the first side surface of the electrode body, and the electrode body is inserted into the battery case in that state. FIG. 9 is a plan view showing an intermediate of the electrode assembly included in the battery shown in FIG. FIG. 10 is a perspective view schematically showing an electrode body included in the battery shown in FIG. FIG. 11 is a development view of the insulating tape used in the battery according to the second embodiment. FIG. 12 is a view showing a state in which the first insulating portion of the insulating tape is attached to the bottom surface of the electrode body and the bottom surface of the first side surface in the battery according to the second embodiment. FIG. 13 is a view showing a first side surface of the electrode body when the electrode body is completely inserted into the battery case in the battery according to Embodiment 2. FIG. 14 is a view showing a second side surface of the electrode body when the electrode body is completely inserted into the battery case, in the battery according to Embodiment 2.

[Embodiment]
Hereinafter, embodiments will be described with reference to the drawings. The same or corresponding components in the drawings have the same reference characters allotted, and the same description will not be repeated.

First Embodiment
(Battery configuration)
FIG. 1 is a perspective view showing an outline of a battery 100 according to the first embodiment. Battery 100 is a so-called prismatic battery, and has a substantially flat rectangular shape. Hereinafter, for convenience of explanation, the short side direction (x direction) of the wide side of the battery 100 is the width direction, and the direction (y direction) perpendicular to the wide side is perpendicular to the thickness direction, the width direction and the thickness direction. The direction (z direction) is referred to as the height direction.

  As shown in FIG. 1, the battery 100 includes a battery case 1 and an electrode body 2. The battery case 1 and the electrode body 2 are both flat. The battery case 1 accommodates the electrode body 2. In the battery case 1, an electrolytic solution (not shown) is also accommodated.

  Battery case 1 includes a side wall 11, a bottom 12, and a lid 14. The side wall portion 11, the bottom portion 12, and the lid 14 are not particularly limited, but are made of, for example, a metal such as an aluminum alloy. The side wall 11 and the bottom 12 are integrally formed. The side wall portion 11 has a pair of flat plate portions 111 facing each other and a pair of arc portions 112. In addition, in FIG. 1, the sealing stopper 4 and the negative electrode terminal 32 which are mentioned later are also shown.

  The electrode body 2 is housed in the battery case 1 and includes an upper surface which is a surface from which electricity is taken out, a bottom surface located on the opposite side to the upper surface, a first side surface 20a which is a wide side surface, and The second side 20b is narrower than the side 20a. As described later, the bottom surface of the electrode body 2, the bottom surface side of the first side surface 20a, and the bottom surface side of the second side surface 20b are covered with an insulating tape which is an insulator.

  FIG. 2 is a cross-sectional view taken along a line II-II of the battery 100 shown in FIG.

  The side wall portion 11 has a flat cylindrical shape. The side wall portion 11 is formed in a cylindrical shape in which the dimension in the thickness direction is smaller than the dimension in the width direction. More specifically, the side wall portion 11 includes a pair of flat plate portions 111 and a pair of arc portions 112 which face each other. Each arc part 112 is provided in the both ends of the thickness direction of a pair of flat parts 111, and connects flat parts 111 mutually. However, the shape of the side wall part 11 is not limited to this, For example, square cylinder shape or elliptical cylinder shape etc. may be sufficient. Each outer surface of the flat plate portion 111 constitutes a wide side surface in the battery 100 having a substantially flat rectangular shape. Each outer surface of the arc portion 112 constitutes a narrow side surface of the battery 100.

  The maximum length in the height direction of the side wall portion 11 is larger than the maximum length in the width direction and the thickness direction of the side wall portion 11. Thus, the battery case 1 has a vertically-long, substantially rectangular shape in a side view.

  The bottom 12 seals one end in the height direction of the battery case 1. The bottom portion 12 constitutes the case main body 10 together with the side wall portion 11. The bottom 12 preferably has a thickness greater than that of the side wall 11.

  The case body 10 has an opening 101 at the end opposite to the bottom 12 in the height direction. The case body 10 can be formed, for example, by deep drawing a metal plate such as an aluminum alloy. Hereinafter, in the height direction, the side where the opening 101 is located may be referred to as the upper side, and the side where the bottom portion 12 is located may be referred to as the lower side.

  As shown in FIG. 2, the lid 14 closes the opening 101 of the case body 10. The lid 14 has an attachment hole 141 and an injection hole 142. The mounting hole 141 and the liquid injection hole 142 respectively penetrate the lid 14 in the height direction.

  The insulating member 31 and the negative electrode terminal 32 are attached to the attachment hole 141. The insulating member 31 insulates the negative electrode terminal 32 and the lid 14. The insulating member 31 can be made of, for example, polypropylene or the like. The negative electrode terminal 32 can be made of, for example, stainless steel or the like.

  The insulating member 31 has a substantially cylindrical shape and is inserted into the mounting hole 141. The negative electrode terminal 32 has a substantially columnar shape and is inserted into the insulating member 31. That is, the insulating member 31 is disposed between the negative electrode terminal 32 and the lid 14. The insulating member 31 and a part of the negative electrode terminal 32 are exposed to the outside of the battery case 1 from the lid 14.

  A lead plate 33 made of, for example, stainless steel is provided on the inner surface of the lid 14. The lead plate 33 is connected to the negative electrode terminal 32. An insulating member 34 is disposed between the lead plate 33 and the lid 14.

  In the battery case 1, an insulating plate 35 is disposed between the negative electrode terminal 32 and the electrode body 2. The insulating plate 35 prevents a short circuit from occurring between the negative electrode terminal 22 and the electrode body 2.

  The liquid injection hole 142 is used when injecting an electrolytic solution (not shown) into the battery case 1. The liquid injection hole 142 is sealed by the sealing plug 4.

  The electrode body 2 includes a positive electrode 21, a negative electrode 22, and a separator 23. The separator 23 is disposed between the positive electrode 21 and the negative electrode 22. The electrode body 2 is a wound body formed by laminating and winding the positive electrode 21, the negative electrode 22, and the separator 23. However, the structure of the electrode body 2 is not limited to this, For example, the laminated body on which the positive electrode, the separator, and the negative electrode were laminated | stacked in order may be sufficient.

  The positive electrode lead 24 is connected to the positive electrode 21. The positive electrode lead 24 is also connected to the lid 14. That is, the positive electrode 21 is electrically connected to the battery case 1 via the positive electrode lead 24. Therefore, the battery case 1 functions as a positive electrode terminal of the battery 100.

  The negative electrode lead 25 is connected to the negative electrode 22. The negative electrode lead 25 is also connected to the lead plate 33. As described above, the lead plate 33 is connected to the negative electrode terminal 32. Thus, the negative electrode 22 is electrically connected to the negative electrode terminal 32 through the negative electrode lead 25 and the lead plate 33.

  The bottom surface of the electrode body 2, the bottom surface side of the first side surface 20a, and the bottom surface side of the second side surface 20b are covered with an insulating tape 40 which is an insulator.

  FIG. 3 is a developed view of the insulating tape 40 used in the battery 100 according to the first embodiment. The x direction and the y direction in FIG. 3 coincide with the x direction and the y direction shown in FIG. As shown in FIG. 3, in the unfolded state, the insulating tape 40 has a cross shape.

  The insulating tape 40 has a first insulating portion 401 covering the bottom surface of the electrode body 2 and the bottom surface side of the first side surface 20a, and a second insulating portion 402 covering the bottom surface side of the second side surface 20b of the electrode member 2. . However, the first insulating portion 401 may cover not only the bottom surface of the electrode body 2 and the bottom surface side of the first side surface 20 a but also a part of the second side surface 20 b of the electrode body 2. The second insulating portion 402 may cover not only the bottom surface side of the second side surface 20 b of the electrode body 2 but also a part of the first side surface 20 a of the electrode body 2. In FIG. 3, the second insulating portion 402 is hatched.

  The first insulating portion 401 has a rectangular shape. However, the shape of the first insulating portion 401 is not limited to a rectangle.

  In the state in which the insulating tape 40 is developed, the second insulating portion 402 is provided on both sides of the first insulating portion 401 in the width direction (x direction) from the center position of the first insulating portion 401 in the thickness direction (y direction). It is provided projecting. The bottom surface side of the second side surface 20 b of the electrode body 2 is covered by the two second insulating portions 402 provided on both outer sides in the width direction of the first insulating portion 401.

  In the state where the insulating tape 40 is developed, the length L1 of the boundary between the first insulating portion 401 and the second insulating portion 402 is the first insulating portion 401 in the direction (thickness direction, y direction) parallel to the boundary. Shorter than the length L2. The boundary between the first insulating portion 401 and the second insulating portion 402 is a line that forms the boundary between the first insulating portion 401 and the second insulating portion 402. The length L1 of the boundary, that is, the length L1 in the thickness direction (y direction) of the second insulating portion 402 is set to the second side 20b of the electrode body 2 in order to cover the second side 20b of the electrode body 2. Longer than the perimeter length.

  However, if the length L1 of the boundary line is as long as the length L2 of the first insulating portion 401 in the y direction, the second insulating portion 402 may completely cover the second side surface 20b of the electrode body 2. become unable. Therefore, the length L1 of the boundary between the first insulating portion 401 and the second insulating portion 402 is longer than the length of the outer periphery of the second side surface 20b of the electrode body 2 by a predetermined length. The predetermined length is a length such that the first insulating portion 401 of the insulating tape 40 can be neatly attached to the second side surface 20b of the electrode body 2 by a method described later.

  In the state where the insulating tape 40 is developed, the length L3 in the width direction (x direction) of the first insulating portion 401 is longer than the length in the width direction (x direction) of the first side surface 20a of the electrode body 2. Since the length L3 in the width direction (x direction) of the first insulating portion 401 is longer than the length in the width direction (x direction) of the first side face 20a of the electrode body 2, the first insulating portion 401 of the insulating tape 40 Thus, the first side surface 20 a on the bottom side of the electrode body 2 can be completely covered.

  In the state where the insulating tape 40 is developed, the length L4 in the width direction (x direction) of the second insulating portion 402 of the insulating tape 40 corresponds to the height to which the second side surface 20b of the electrode body 2 is covered. Will be decided accordingly.

  The method of affixing the insulating tape 40 to the electrode body 2 will be described. First, the first insulating portion 401 of the insulating tape 40 is attached to the bottom surface of the electrode body 2 and the bottom surface side of the first side surfaces 20 a facing each other. Specifically, the width direction (x direction) of the insulating tape 40 and the width direction (x direction) of the electrode body 2 are made to coincide with each other, and the center position of the first insulating portion 401 of the insulating tape 40 and the electrode body 2 The insulating tape 40 is attached to the bottom surface of the electrode body 2 in a state in which the center position of the bottom surface is aligned with the center position. Then, a portion of the first insulating portion 401 of the insulating tape 40 that is not attached to the bottom surface of the electrode body 2 is bent along the first side surface 20 a of the electrode body 2 to form the first side surface 20 a of the electrode body 2. Stick on both sides of

  FIG. 4 is a view showing a state in which the first insulating portion 401 of the insulating tape 40 is attached to the bottom surface of the electrode body 2 and the bottom surface side of the first side surface 20a.

  In a state where the first insulating portion 401 of the insulating tape 40 is attached to the bottom surface of the electrode body 2 and the bottom surface side of the first side surface 20a (see FIG. 4), the opening 101 of the case body 10 of the battery case 1 is formed. Then, insert it into the battery case 1. At this time, as shown in FIG. 5, in the process of inserting the electrode body 2 into the battery case 1, the second insulating portion 402 of the insulating tape 40 is naturally folded upward, and the second side surface of the electrode body 2 is It is pasted to 20b.

  As described above, the length L1 of the boundary between the first insulating portion 401 and the second insulating portion 402 of the insulating tape 40 is shorter than the length L2 of the first insulating portion 401 in the direction parallel to the boundary. . Thereby, when inserting the electrode body 2 into the battery case 1, the second insulating portion 402 of the insulating tape 40 is folded upward without being crushed, so that the second insulating portion 402 of the insulating tape 40 is not It can be affixed so as to completely cover the bottom side of the second side 20b.

  FIG. 6 is a view showing the first side face 20 a of the electrode assembly 2 when the insertion of the electrode assembly 2 into the battery case 1 is completed. FIG. 7 is a view showing a second side surface 20 b of the electrode assembly 2 when the insertion of the electrode assembly 2 into the battery case 1 is completed. As shown in FIG. 7, the insulating tape 40 is attached so as to completely cover the bottom surface side of the second side surface 20 b of the electrode assembly 2. Also, the first insulating portion 401 is attached to the bottom surface of the electrode body 2 and the bottom surface side of the first side surface 20a, and the second insulating portion 402 is attached to the bottom surface side of the second side surface 20b. The first insulating portion 401 and the second insulating portion 402 are not connected on the side surface of the electrode body 2.

  Conventionally, a rectangular insulating tape which is slightly larger than the bottom surface of the electrode assembly is attached to the bottom surface of the electrode assembly, and then bent toward the first side surface 20a and attached to the bottom surface of the first side surface 20a. The body was inserted into the case body (see Figure 8). However, in this method, when the electrode body is inserted into the case main body, a portion of the insulating tape not attached to the electrode body is not attached so as to completely cover the second side face 20b of the electrode body, A state occurs in which the insulating tapes stick to each other. Therefore, on the bottom side of the second side face 20b of the electrode assembly, there may be a portion not covered with the insulating tape. This is clearly divided into a first insulating portion that covers the bottom surface of the electrode body and the bottom surface side of the first side surface 20a, and a second insulating portion that covers the bottom surface side of the second side surface 20b of the electrode body. It is due to the fact that it does not have an irregular shape.

(Method of manufacturing battery)
Hereinafter, an outline of a method of manufacturing the battery 100 will be described. However, the method of manufacturing the battery 100 is not limited to the example described in the present embodiment.

  First, the electrode body 2 is formed. FIG. 9 is a plan view showing an outline of an intermediate 2i produced in forming the electrode body 2. As shown in FIG. In order to produce an intermediate 2i, a strip-shaped positive electrode 21, a negative electrode 22, and a separator 23 are prepared.

  The positive electrode 21 includes a positive electrode current collector 211 and a positive electrode mixture layer 212. The positive electrode current collector 211 is formed in a band shape. The positive electrode current collector 211 is formed of, for example, a foil such as aluminum or titanium, a plain woven wire mesh, an expanded metal, a ras mesh, or a punching metal.

  The positive electrode mixture layer 212 is formed on both sides of the positive electrode current collector 211. The positive electrode mixture layer 212 is provided on the positive electrode current collector 211 so as to expose a part of the positive electrode current collector 211. The positive electrode mixture layer 212 exposes, for example, one end of the positive electrode current collector 211 in the long side direction. The positive electrode lead 24 is connected to a portion of the positive electrode current collector 211 exposed from the positive electrode mixture layer 212.

  The positive electrode mixture layer 212 is formed by mixing a positive electrode active material, a conductive additive, and a binder. As the positive electrode active material, for example, lithium manganate, lithium nickel composite oxide, lithium cobalt composite oxide, lithium nickel cobalt composite oxide, vanadium oxide, molybdenum oxide or the like can be used. For example, graphite, carbon black, or acetylene black can be used as the conductive aid. As the binder, for example, polyimide, polyamide imide, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) or the like can be used alone or in combination.

  The negative electrode 22 includes a negative electrode current collector 221 and a negative electrode mixture layer 222. The negative electrode current collector 221 is formed in a band shape. The negative electrode current collector 221 is formed of, for example, a foil such as copper, nickel, or stainless steel, a plain woven wire mesh, an expanded metal, a lath mesh, or a punching metal.

  The negative electrode mixture layer 222 is formed on both sides of the negative electrode current collector 221. The negative electrode mixture layer 222 is provided on the negative electrode current collector 221 so as to expose a part of the positive electrode current collector 211. The negative electrode mixture layer 222 exposes, for example, one end in the long side direction of the negative electrode current collector 221. The negative electrode lead 25 is connected to a portion of the negative electrode current collector 221 exposed from the negative electrode mixture layer 222.

  The negative electrode mixture layer 222 is formed by mixing a negative electrode active material and a binder. As the negative electrode active material, for example, natural graphite, mesophase carbon, or amorphous carbon can be used. As a binder, for example, cellulose such as carboxymethyl cellulose (CMC) and hydroxypropyl cellulose (HPC), rubber binder such as styrene butadiene rubber (SBR), acrylic rubber etc., PTFE, PVDF, etc. may be used alone or in combination. it can.

  The separator 23 can be formed of, for example, a porous film or non-woven fabric such as polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or polyphenyl sulfide (PPS). .

  The negative electrode 22, the separator 23, the positive electrode 21, and the separator 23 are stacked in this order to produce an intermediate 2i. In the intermediate 2i shown in FIG. 9, the separator 23 on the positive electrode 21 is not shown. The separators 23 are disposed on both sides of the positive electrode 21. The positive electrode 21 is disposed between the two separators 23. In addition, the lamination | stacking form of the negative electrode 22, the positive electrode 21, and the separator 23 is not restricted to this. For example, the separator 23, the negative electrode 22, the separator 23, and the positive electrode 21 can be stacked in this order. The negative electrode lead 25 is disposed at the end opposite to or the same end as the end where the positive electrode lead 24 is disposed in the long side direction of the intermediate 2i.

  The produced intermediate 2i is wound and pressed to be formed into a flat shape. Thereby, the spiral electrode body 2 shown in FIG. 10 is obtained. From one surface (upper surface) in the winding axis direction of the electrode body 2, a positive electrode lead 24 and a negative electrode lead 25 for taking out electricity project. The side surface of the wound intermediate 2i may be covered with an insulating tape.

  Subsequently, as described above, the first insulating portion 401 of the insulating tape 40 is attached to the bottom surface of the electrode body 2 and the bottom surface side of the first side surfaces 20a facing each other (see FIG. 4). Are inserted into the battery case 1 from the opening 101 of the case main body 10 of the battery case 1 (see FIG. 5). In the process of inserting the electrode body 2 into the battery case 1, the second insulating portion 402 of the insulating tape 40 is naturally folded upward and is attached to the bottom side of the second side surface 20 b of the electrode body 2.

  As shown in FIG. 2, after inserting the electrode assembly 2 into the battery case 1, the insulating plate 35 is disposed on the electrode assembly 2 of the battery case 1. The tip of the positive electrode lead 24 protruding from the upper surface of the electrode body 2 is connected to the lid 14. The tip of the negative electrode lead 25 protruding from the upper surface of the electrode body 2 is connected to the lead plate 33. The insulating member 31, the negative electrode terminal 32, the lead plate 33, and the insulating member 34 are assembled to the lid 14.

  Next, the lid 14 is joined to the outer peripheral edge portion of the opening 101 in the case main body 10. The lid 14 can be joined to the case body 10 by welding, for example. Thereby, the opening 101 of the case body 10 is closed by the lid 14.

Thereafter, an electrolyte (not shown) is injected into the battery case 1 from the injection hole 142. The electrolytic solution is a solution in which a lithium salt is dissolved in an organic solvent. As an organic solvent, for example, vinylene carbonate (VC), propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (MEC), or γ-butyrolactone or the like can be used alone or in combination of two or more. As a lithium salt, for example, LiPF ₆ , LiBF ₄ , or LiN (CF ₃ SO ₂ ) ₂ can be used.

  After the electrolytic solution (not shown) is injected into the battery case 1, the liquid injection hole 142 is sealed by the sealing plug 4. The sealing plug 4 is joined to the outer peripheral edge portion of the liquid injection hole 142 in the lid 14 by, for example, welding or the like. Thereby, the battery 100 can be obtained.

(Effect of Embodiment 1)
In the battery 100 according to the first embodiment, the insulating tape 40 covers the bottom surface side of the electrode body 2 and the bottom surface side of the first side surface 20a, and the bottom surface side of the second side surface 20b of the electrode body 2 The first insulating portion 401 and the second insulating portion 402 are not connected to each other on the side surface of the electrode body 2. That is, on the side surface of the electrode body 2, the first insulating portion 401 and the second insulating portion 402 are not continuously connected. With such a configuration, the electrode assembly 2 is attached to the battery case 1 in a state where the first insulating portion 401 of the insulating tape 40 is attached to the bottom surface of the electrode assembly 2 and the bottom surface of the first side surface 20a (see FIG. 4). In the process of inserting, the second insulating portion 402 of the insulating tape 40 can be naturally folded upward and can be attached so as to completely cover the second side surface 20 b of the electrode body 2. (See Figure 7). Further, in the process of inserting the electrode body 2 into the battery case 1, the second insulating portion 402 of the insulating tape 40 is naturally folded upward, so a process of stretching the insulating tape on the second side surface 20 b of the electrode body 2 It does not become complicated and can be pasted easily.

  Further, even when the insulating tape 40 is attached to the second side face 20b of the electrode body 2 by a machine or a human hand, the insulating tape 40 can be attached easily according to the battery 100 according to the present embodiment. That is, the insulating tape 40 separately covers the bottom surface side of the second side surface 20 b of the electrode body 2 separately from the first insulating portion 401 covering the bottom surface side of the electrode body 2 and the bottom surface side of the first side surface 20 a. Since the portion 402 is provided and the first insulating portion 401 and the second insulating portion 402 are not connected on the side surface of the electrode body 2 and are clearly distinguished, the second insulating portion 402 By bending, the second side surface 20b of the electrode body 2 can be easily attached.

  Furthermore, according to the battery 100 according to the first embodiment, the insulating tape 40 can be beautifully attached not only to the bottom side of the first side 20a of the electrode body 2 but also to the bottom side of the second side 20b. The entire side surface on the bottom side of the electrode body 2 can be completely covered with the insulating tape 40. Thereby, even when the battery 100 falls, particularly from the corner of the bottom of the battery 100, the contact between the battery case 1 also functioning as a positive electrode terminal and the negative electrode 22 of the electrode body 2 can be prevented. This is specifically described below.

  As described above, the battery case 1 has a vertically-long, substantially rectangular shape in a side view. Therefore, when the battery 100 falls from the corner of the battery case 1, the battery 100 is more likely to be inclined in the direction of the bottom 12 than in the direction of the arc portion 112. In this case, a force larger than the force acting on the bottom acts on the arc portion 112, and a relatively large deformation may occur in a portion near the bottom portion of the arc portion 112.

  Also, for example, when forming the battery case 1 by deep drawing a metal plate such as an aluminum alloy, the thickness of the corner portion is usually the thickness of the side wall portion 11 because the metal plate is largely bent at the corner portion It may be smaller than the thickness and thickness of the bottom 12. In this case, the corner portion is more likely to be deformed when the battery 100 falls, as compared with the side wall portion 11 and the bottom portion 12.

  Generally, when the electrode body in the battery case is a wound body, when the corner of the battery case is deformed by the drop of the battery, the electrode body may be distorted. At this time, if the side surface on the bottom side of the electrode body is not completely covered with the insulating tape, there is a possibility that the battery case functioning also as a positive electrode terminal and the negative electrode of the electrode body contact and short circuit.

  However, in the battery 100 according to the present embodiment, the entire side surface on the bottom surface side of the electrode body 2 is completely covered with the insulating tape 40, so even if the battery 100 drops and the corner of the battery case 1 is deformed. The contact between the negative electrode 22 of the electrode body 2 and the battery case 1 can be prevented.

  Thus, according to the battery 100 according to the present embodiment, it is possible to prevent contact between the negative electrode of the electrode body 2 and the battery case 1 which also functions as a positive electrode terminal when it is dropped.

Second Embodiment
FIG. 11 is a development view of the insulating tape 110 used in the battery 100 according to the second embodiment. As shown in FIG. 11, in the unfolded state, the insulating tape 110 has a shape in which cuts extending from the four corners of the rectangle toward the inside of the rectangle are included. A line connecting the end points of two notches directed inward from one end of the insulating tape 110 in the width direction is parallel to the thickness direction (y direction) of the rectangular insulating tape 110, as shown in FIG. Similarly, a line connecting the end points of two notches extending inward from the other end in the width direction of the insulating tape 110 is also parallel to the thickness direction (y direction) of the rectangular insulating tape 110.

  The insulating tape 110 has a first insulating portion 1101 covering the bottom of the electrode body 2 and the bottom side of the first side 20a, and a second insulating portion 1102 covering the bottom of the second side 20b of the electrode 2. . However, the first insulating portion 1101 may cover not only the bottom surface of the electrode body 2 and the bottom surface side of the first side surface 20 a but also a part of the second side surface 20 b of the electrode body 2. Further, the second insulating portion 1102 may cover not only the bottom side of the second side surface 20 b of the electrode body 2 but also a part of the first side surface 20 a of the electrode body 2. In FIG. 11, the second insulating portion 1102 is hatched.

  As shown in FIG. 11, the first insulating portion 1101 and the second insulating portion 1102 can be clearly distinguished by cutting the four corners of the rectangular insulating tape 110. The bottom surface side of the second side surface 20 b of the electrode body 2 is covered by the two second insulating portions 1102.

  When the insulating tape 110 is developed, the length L11 of the boundary between the first insulating portion 1101 and the second insulating portion 1102 is the length of the first insulating portion 1101 in the direction (y direction) parallel to the boundary. It is shorter than L12. The length L11 of the boundary line is longer than the length of the outer periphery of the second side surface 20b of the electrode body 2 in order to cover the bottom side of the second side surface 20b of the electrode body 2.

  However, if the length L11 of the boundary line is as long as the length L12 of the first insulating portion 1101 in the y direction, the second insulating portion 1102 completely covers the second side surface 20b of the electrode body 2. become unable. Therefore, the length L11 of the boundary between the first insulating portion 1101 and the second insulating portion 1102 is longer than the length in the thickness direction of the second side surface 20b of the electrode body 2 by a predetermined length. The predetermined length is a length that the first insulating portion 1101 of the insulating tape 110 can be attached so as to completely cover the second side surface 20 b of the electrode body 2.

  Further, in the width direction (x direction) of the first insulating portion 1101, the length L13 of the shortest part is longer than the length in the width direction (x direction) of the first side face 20a of the electrode body 2. Since the length L13 of the shortest part in the width direction (x direction) of the first insulating portion 1101 is longer than the length in the width direction (x direction) of the first side face 20a of the electrode assembly 2, the first insulating portion 1101 The bottom surface side of the first side surface 20 a of the electrode body 2 can be completely covered by the 1 insulating portion 1101.

  In the state where the insulating tape 110 is developed, the length L14 in the x direction of the second insulating portion 1102 is appropriately determined depending on the height to which the second side surface 20b of the electrode body 2 is to be covered.

  The method of affixing the insulating tape 110 to the electrode body 2 will be described. First, the first insulating portion 1101 of the insulating tape 110 is attached to the bottom surface of the electrode body 2 and the bottom surface side of the opposing first side surface 20a. Specifically, the width direction (x direction) of the insulating tape 110 and the width direction (x direction) of the electrode body 2 are made to coincide with each other, and the center position of the first insulating portion 1101 of the insulating tape 110 and the electrode body 2 The insulating tape 110 is attached to the bottom surface of the electrode body 2 in a state in which the center position of the bottom surface is aligned with the center position. Then, a portion of the first insulating portion 1101 of the insulating tape 110 which is not attached to the bottom surface of the electrode body 2 is bent along the first side surface 20 a of the electrode body 2 to form the first side surface 20 a of the electrode body 2. Stick on both sides of FIG. 12 is a view showing a state in which the first insulating portion 1101 of the insulating tape 110 is attached to the bottom surface of the electrode body 2 and the bottom surface side of the first side surface 20a.

  In a state where the first insulating portion 1101 of the insulating tape 110 is attached to the bottom surface of the electrode body 2 and the bottom surface side of the first side surface 20a (see FIG. 12), the opening 101 of the case body 10 of the battery case 1 is formed. Then, insert it into the battery case 1. At this time, in the process of inserting the electrode body 2 into the battery case 1, the second insulating portion 1102 of the insulating tape 110 is naturally folded upward and is attached to the second side surface 20 b of the electrode body 2. Specifically, in the first insulating portion 1101 of the insulating tape 110, a protruding portion 1101a (see FIG. 12) protruding outward in the width direction (x direction) is folded in the direction of the second side surface 20b of the electrode assembly 2. The second insulating portion 1102 of the insulating tape 110 is bent upward and attached to the second side surface 20 b of the electrode body 2.

  FIG. 13 is a view showing a first side surface 20 a of the electrode assembly 2 when the insertion of the electrode assembly 2 into the battery case 1 is completed. FIG. 14 is a view showing a second side surface 20 b of the electrode assembly 2 when the insertion of the electrode assembly 2 into the battery case 1 is completed.

  The method of manufacturing the battery according to the second embodiment is the same as the method of manufacturing the battery according to the first embodiment described above.

(Effect of Embodiment 2)
In the battery 100 according to the second embodiment, the insulating tape 110 includes a first insulating portion 1101 that covers the bottom of the electrode body 2 and the bottom of the first side 20a, and the bottom of the second side 20b of the electrode 2 The first insulating portion 1101 and the second insulating portion 1102 are not connected to each other on the side surface of the electrode body 2. With such a configuration, the electrode assembly 2 is attached to the battery case 1 in a state where the first insulating portion 1101 of the insulating tape 110 is attached to the bottom surface of the electrode assembly 2 and the bottom surface of the first side surface 20a (see FIG. 12). In the process of insertion, the second insulating portion 1102 of the insulating tape 110 is naturally folded upward and is neatly attached to the second side surface 20 b of the electrode body 2. (See Figure 14). Further, since the second insulating portion 1102 of the insulating tape 110 is naturally folded upward in the process of inserting the electrode body 2 into the battery case 1, the process of stretching the insulating tape on the second side surface 20 b of the electrode body 2 is It does not become complicated and can be pasted easily.

  Further, even when the insulating tape 110 is attached to the second side face 20b of the electrode body 2 by a machine or a human hand, the insulating tape 110 can be easily attached according to the battery 100 according to the present embodiment. That is, in the insulating tape 110, the second insulating portion 1102 covering the second side surface 20 b of the electrode body 2 is different from the first insulating portion 1101 covering the bottom surface of the electrode body 2 and the bottom side of the first side surface 20 a. Since the first insulating portion 401 and the second insulating portion 402 are not connected on the side surface of the electrode body 2 and are clearly distinguished from each other, the second insulating portion 1102 is bent. Can be easily attached to the second side surface 20 b of the electrode body 2.

  Furthermore, since the insulating tape 110 can be neatly attached not only to the bottom surface side of the first side surface 20a of the electrode body 2 but also to the bottom surface side of the second side surface 20b, the entire side surface on the bottom surface side of the electrode body 2 is It can be completely covered with the insulating tape 110. Thereby, even if the battery 100 falls, particularly from the corner of the bottom of the battery 100 for the reason described in the first embodiment, the battery case 1 also functions as a positive electrode terminal and the negative electrode of the electrode assembly 2. It can prevent contact.

  As mentioned above, although embodiment was described, this invention is not limited to the said embodiment, A various change is possible unless it deviates from the meaning. For example, in the above-described embodiment, an insulating tape having adhesive strength is used as an insulator covering the bottom surface and the bottom surface side of the side surface of the electrode body 2, but an insulator having no adhesive power may be used. In this case, an insulator can be attached to the electrode body 2 using an adhesive.

  In the second embodiment, the insulating tape 110 has a shape in which cuts extending from the four corners of the rectangle toward the inside of the rectangle are included, for example, a shape in which cuts extending from the four locations of the oval toward the inside of the oval are included. May be That is, the shape of the insulating tape 110 is not limited to a rectangle.

  Moreover, the method of sticking the 2nd insulation part 402 (1102) of the insulating tape 40 (110) on the 2nd side 20b of the electrode body 2 is not limited to the method mentioned above, It is made to stick by a machine or a human hand. It is also good.

100: battery, 1: battery case, 2: electrode body, 20a: first side, 20b: second side, 21: positive electrode, 22: negative electrode, 23: separator, 40: insulating sheet (insulator), 401 1st insulation part, 402: 2nd insulation part, 110: insulation sheet (insulator), 1101: 1st insulation part, 1102: 2nd insulation part

Claims (1)

A flat electrode body including a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode;
A battery case for housing the electrode body;
Rectangular insulation having a first insulating portion covering the bottom surface of the electrode body and the bottom surface side of the first side surface, and a second insulating portion covering the bottom surface side of the second side surface having a width smaller than the first side surface Body,
Equipped with
The insulator includes four notches extending from the four corners of the rectangle to the inside of the rectangle, and the insulator divides the insulator into the first insulating portion and the second insulating portion,
In the battery, the first insulating portion and the second insulating portion are not connected on the side surface of the electrode body.

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