JP2008204686A - Battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery which has high reliability without possibility of lowering an open-circuit voltage even if internal short circuit occurs by preventing floating, tilting or the like of a frame body by stabilizing an insertion state of the frame body when a resin-made insulating plate called the frame body is inserted into the upper part of an electrode body in a bottomed case in order to prevent the internal short circuit from occurring by contact of a lead terminal led out from an electrode plate with the interior or the like of the bottomed case. <P>SOLUTION: By installing recessed parts 5 and protruding parts 6 or the like on the inner side surface of the bottomed case 1 as engagement parts engaged with a part of the frame body 4, when the frame body 4 is arranged on the upper part of the electrode body 3 in the bottomed case 1, the frame body 4 is held by these engagement parts, and floating, tilting, or the like of the frame body can be suppressed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a battery in which a frame is disposed between a sealing body and an electrode body, and more particularly to a configuration for preventing an internal short circuit of a prismatic lithium ion secondary battery.

  In recent years, consumer electronic devices such as notebook computers, mobile phones, and AV devices are rapidly becoming portable and cordless, and secondary batteries that are small, lightweight, and have high energy density to drive power for these electronic devices. The demand for is increasing.

  Non-aqueous electrolyte secondary batteries, in particular lithium ion secondary batteries, are batteries having high voltage and high energy density, and are therefore mainly used in notebook computers, mobile phones, AV equipment and the like. In particular, prismatic lithium ion secondary batteries are being actively developed because they are excellent in load characteristics and life characteristics, are suitable for thinning electronic devices, and have good space efficiency.

In a rectangular lithium ion secondary battery, lead terminals are attached to both electrode plates of an electrode body, and the lead terminals are connected to internal terminals, and electricity is taken out through external terminals connected to the internal terminals. When using a metal bottomed case, the lead terminal connected to the electrode plate having the same polarity as the bottomed case is directly connected to the bottomed case or a metal lid connected to the bottomed case. It is connected to the. The lead terminal connected to the pole plate with the polarity different from that of the metal bottomed case is connected to the internal terminal, and the internal terminal is insulated by the bottomed case or the metal lid and gasket. When the electrode body is moved by the above, the lead terminal is deformed, and there is a possibility that an internal short circuit occurs due to contact with the inside of the bottomed case. In order to prevent this, a resin insulating plate called a frame body is generally installed on top of the electrode body housed in the bottomed case (see, for example, Patent Documents 1 and 2).
JP-A-8-69815 JP 2001-229898 A

  However, since such a conventional frame only has a resin insulating plate called a frame disposed above the electrode body housed in the bottomed case, this frame is used as an electrode in the bottomed case. When inserting into the upper part of the body, the inserted state of the frame body may become unstable due to lot-to-lot variations such as the inner dimensions of the bottomed case and the electrode body. As a result, the frame body is lifted or tilted, and the lead terminal is deformed to contact the inner side surface of the bottomed case and the like, thereby causing an internal short circuit and reducing the open circuit voltage.

  The present invention solves the above-mentioned problem, and stabilizes the insertion state of the frame body when the frame body is inserted into the upper part of the electrode body in the bottomed case, and the lead terminal is deformed to deform the inner surface of the bottomed case. It is an object of the present invention to provide a highly reliable battery that does not cause a short circuit due to an internal short circuit due to contact therewith.

In order to solve the above-described problems, the present invention accommodates an electrode body and an electrolytic solution, in which a strip-like positive electrode plate and a negative electrode plate connected with lead terminals are stacked or spirally wound via a separator. A bottomed case and a sealing body that seals the opening of the bottomed case are provided, and a frame for insulating the bottomed case from the lead terminal or the electrode body is disposed between the sealing body and the electrode body. In the battery, an engagement portion that engages with a part of the frame is provided on an inner surface of the bottomed case.

  According to this configuration, since the engagement portion that engages with a part of the frame body is provided on the inner surface of the bottomed case, the engagement portion causes the engagement when the frame body is disposed on the upper portion of the electrode body in the bottomed case. The frame is held, and it is possible to suppress the floating and tilting of the frame. As a result, even when the electrode body moves due to vibration or drop impact, the open circuit voltage may decrease due to internal short circuit due to deformation of the lead terminal, etc. A highly reliable battery without any problem can be obtained.

  According to the present invention, when the frame body is inserted into the upper portion of the electrode body in the bottomed case by providing the engaging portion that engages with a part of the frame body on the inner surface of the bottomed case, the bottomed case The frame insertion state does not become unstable due to lot-to-lot variations such as the internal dimensions of the electrode and the electrode body, so that the floating and tilting of the frame can be suppressed. As a result, it is possible to provide a highly reliable battery in which the lead terminal is deformed and contacts the inner side surface of the bottomed case to cause an internal short circuit and the open circuit voltage does not decrease.

  In the present invention, an electrode body formed by laminating or winding a strip-like positive electrode plate and a negative electrode plate connected with lead terminals via a separator, and a bottomed case containing an electrolyte therein, and this A battery comprising a sealing body for sealing an opening of a bottom case, and a frame for insulating the bottomed case and a lead terminal or an electrode body between the sealing body and the electrode body. An engaging portion that engages with a part of the frame is provided on the inner surface of the bottom case.

  According to this configuration, when the frame body is inserted into the upper part of the electrode body in the bottomed case, the frame body is held by the engaging portion. Therefore, the insertion state of the frame body does not become unstable, and the floating and inclination of the frame body can be suppressed.

  Further, as the engaging portion, one of the inner side surface of the bottomed case and the outer peripheral edge of the frame body may be a concave portion and the other may be a convex portion, and the concave and convex portions may be fitted.

  According to this configuration, since the frame body is positioned by fitting the concave and convex portions, the frame body can be reliably held without being displaced in the vertical direction. Further, the holding position of the frame body with respect to the bottomed case can be accurately defined by the position where the uneven portion is provided.

  Moreover, it is good also as a structure which provides a convex part in the inner surface of a bottomed case as said engaging part, and engages the lower part of this convex part and a part of outer periphery of the said frame.

  According to this configuration, the float and inclination of the frame can be suppressed with a simple configuration in which the convex portion is provided on the inner side surface of the bottomed case. For example, even when a frame with a structurally provided protrusion is used, the protrusion can be engaged with a protrusion provided on the inner surface of the bottomed case to lift or tilt the frame. Can be suppressed.

  Moreover, it is good also as a structure which provides a convex part in the inner surface of a bottomed case as said engaging part, and engages the lower end of this convex part and the upper end part of the outer periphery of the said frame.

  According to this configuration, it is possible to suppress the floating or inclination of the frame body without particularly processing the frame body by merely providing the convex portion on the bottomed case side.

  Moreover, you may provide the convex part of the inner surface of the said bottomed case by an extrusion process.

  According to this configuration, the convex portion can be easily provided on the inner surface of the bottomed case. Moreover, since it can produce by performing the process which provides a convex part in a bottomed case without a convex part, the change of the protrusion part of a convex part, a position, a shape, etc. can be performed easily.

  Moreover, it is good also as a structure which provides a level | step-difference part in the inner surface of a bottomed case as said engaging part, and engages the lower part of this level | step-difference part and a part of outer periphery of the said frame.

  According to this configuration, the float and inclination of the frame can be suppressed with a simple configuration in which a step portion is provided in the vicinity of the opening of the bottomed case.

  Moreover, it is good also as a structure which provides a step part in the inner surface of a bottomed case as said engaging part, and engages the lower part of this step part and the upper end part of the outer periphery of the said frame.

  According to this configuration, the float or inclination of the frame can be suppressed without providing any special processing to the frame simply by providing the stepped portion on the bottomed case side.

  In addition, by providing the engagement portion on the inner side surface of the bottomed case in this way, the insertion state of the frame body does not become unstable due to lot-to-lot variations such as the inner dimensions of the bottomed case and the electrode body, In addition, even when excessive vibration or drop impact is applied, it is possible to provide a highly reliable battery in which the lead terminal does not come into contact with the inside of the bottomed case to cause an internal short circuit and reduce the open circuit voltage.

  In addition, the engaging portion provided in the bottomed case is preferably provided over the entire circumference of the inner side surface of the bottomed case, but it is also effective to be provided partially on the inner side surface of the bottomed case.

  FIG. 11 is an exploded perspective view showing the structure of the frame and bottomed case of the prismatic lithium ion secondary battery.

  An electrode body 3 formed by winding a strip-shaped negative electrode plate having a lead terminal 2 connected to a metal bottomed case 1 and a positive electrode plate with a separator interposed therebetween is housed. The frame body 4 is provided with a hole portion 4 a on the bottom surface, and the lead terminal 2 is passed through the hole portion 4 a so as to be arranged on the upper portion of the electrode body 3.

(Example 1)
FIG. 1 is a schematic cross-sectional view of the main part of a battery showing the configuration of Example 1 of the present invention.

  An electrode body 3 formed by winding a strip-like negative electrode plate and a positive electrode plate, to which a nickel lead terminal 2 is connected, through a separator made of porous polyethylene was housed in a bottomed case 1 made of aluminum alloy. The frame 4 was made of polypropylene resin in order to insulate the lead terminal 2 from the bottomed case 1 and the electrode body 3. A hole 4 a was provided on the bottom surface of the polypropylene resin frame 4, and the lead terminal 2 was passed through the hole 4 a, and the frame 4 was arranged on the upper part of the electrode body 3.

  At this time, the concave portion 5 as the engaging portion provided on the inner surface of the bottomed case 1 and the convex portion 6 provided on the outer peripheral edge of the frame body 4 were fitted and engaged as shown in FIG.

  In this state, as shown in FIG. 9A, the tip of the lead terminal 2 and the sealing body 7 are laser welded, and the lead terminal 2 is bent as shown in FIG. Arranged in the opening of the bottomed case 1.

  Next, the sealing body 7 and the bottomed case 1 are laser welded, and after pouring a non-aqueous electrolyte into the bottomed case 1 through the liquid injection hole at the top of the sealing body 7, the liquid injection hole is sealed and Example 1 A square lithium ion secondary battery was prepared.

(Example 2)
FIG. 2 is a schematic cross-sectional view of the main part of the battery showing the configuration of Example 2 of the present invention.

  The same as in Example 1 except that the convex portion 8 as the engaging portion provided on the inner surface of the bottomed case 1 and the concave portion 9 provided on the outer peripheral edge of the frame body 4 were engaged as shown in FIG. The produced square lithium ion secondary battery was referred to as Example 2.

(Example 3)
FIG. 3 is a schematic cross-sectional view of the main part of the battery showing the configuration of Example 3 of the present invention.

  Example except that the lower part of the convex part 10 as the engaging part provided on the inner surface of the bottomed case 1 and the upper part of the convex part 11 provided on the outer peripheral edge of the frame body 4 are engaged as shown in FIG. A rectangular lithium ion secondary battery produced in the same manner as in Example 1 was referred to as Example 3.

Example 4
FIG. 4 is a schematic cross-sectional view of the main part of the battery showing the configuration of Example 4 of the present invention.

  The same as in Example 1 except that the lower part of the convex part 12 as the engaging part provided on the inner side surface of the bottomed case 1 and the upper end part of the outer peripheral edge of the frame 4 are engaged as shown in FIG. The produced square lithium ion secondary battery was referred to as Example 4.

(Example 5)
FIG. 5 is a schematic cross-sectional view of the main part of the battery showing the configuration of Example 5 of the present invention.

  Example 1 except that the lower part of the convex part 13 as an engaging part provided on the inner side surface of the bottomed case 1 and the upper end part of the outer peripheral edge of the frame body 4 are engaged as shown in FIG. A square lithium ion secondary battery produced in the same manner was taken as Example 5.

(Example 6)
FIG. 6 is a schematic cross-sectional view of the main part of the battery showing the configuration of Example 6 of the present invention.

  Example 1 except that the stepped portion 14 as the engaging portion provided on the inner surface of the bottomed case 1 and the upper portion of the convex portion 15 provided on the outer surface of the frame body 4 are engaged as shown in FIG. A square lithium ion secondary battery produced in the same manner was designated as Example 6.

(Example 7)
FIG. 7 is a schematic cross-sectional view of the main part of the battery showing the configuration of Example 7 of the present invention.

  It was produced in the same manner as in Example 1 except that the stepped portion 16 as the engaging portion provided on the inner surface of the bottomed case 1 and the upper end portion of the outer peripheral edge of the frame body 4 were engaged as shown in FIG. A square lithium ion secondary battery was taken as Example 7.

(Example 8)
FIG. 8 is a schematic cross-sectional view of the main part of the battery showing the configuration of Example 8 of the present invention.

A stepped portion 17 serving as an engaging portion provided on the inner side surface of the opening of the bottomed case 1 with the increased thickness.
A rectangular lithium ion secondary battery manufactured in the same manner as in Example 1 except that the upper end of the outer peripheral edge of the frame 4 was engaged as shown in FIG.

(Comparative Example 1)
FIG. 10 is a schematic cross-sectional view of the main part of the battery showing the configuration of Comparative Example 1.

  After housing an electrode body 23 formed by winding a strip-like negative electrode plate and a positive electrode plate connected with lead terminals 22 through a separator in the bottomed case 21, the lead terminals 22 and the bottomed case are placed above the electrode body 23. A frame body 24 for insulating 21 and the electrode body 23 was disposed. As shown in FIG. 10, the prismatic lithium ion secondary produced in the same manner as in Example 1 except that the engagement portion that engages with a part of the frame 24 was not provided on the inner surface of the bottomed case 21. The battery was referred to as Comparative Example 1.

  In Examples 1 to 8 and Comparative Example 1, 1000 square lithium ion secondary batteries were produced, and the occurrence rate of internal short circuit after the drop impact test was confirmed. The internal short-circuit occurrence rate was determined by measuring the open circuit voltage before and after the drop impact test of the prismatic lithium ion secondary battery that was almost fully charged, and determining that the open circuit voltage decreased by 100 mV or more as an internal short circuit occurrence product. In the drop impact test, a resin tray capable of storing 200 prismatic lithium ion secondary batteries prepared was used, and 200 prismatic lithium ion secondary battery sealing bodies were stored in the resin tray so that the sealing body faced downward. Then, it was naturally dropped 10 times from the height of 50 cm.

  The results are shown in (Table 1).

  As can be seen from (Table 1), no internal short circuit occurred in Examples 1 to 8, but four internal short circuits occurred in Comparative Example 1. As a result of X-ray fluoroscopic inspection of these four prismatic lithium ion secondary batteries, it was confirmed that the lead terminals 22 were deformed to a position where they were in contact with the inner surface of the bottomed case 21. That is, it is considered that the drop impact test caused a problem such as the floating or tilting of the frame body 24 and the lead terminal 22 and the inner side surface of the bottomed case 21 contacted to cause an internal short circuit, resulting in a decrease in open circuit voltage.

  In other words, the prismatic lithium ion secondary battery manufactured with the configuration of Comparative Example 1 may cause an internal short circuit due to floating or tilting of the frame, but the prismatic lithium ion secondary battery manufactured with the configurations of Examples 1-8. It was found that the reliability against internal short circuit can be greatly improved.

  According to the first to eighth embodiments, the frame 4 is held in the bottomed case 1 by providing the engaging portion where the bottomed case 1 and the frame 4 are engaged. Is considered to have been resolved.

  On the other hand, in Comparative Example 1, since there is no engaging portion for engaging the bottomed case 21 and the frame body 24, the frame body 24 is not held in the bottomed case 21, and it is considered that the frame body 24 is lifted or inclined. .

  Since the battery of the present invention can stabilize the insertion state of the frame body by providing an engagement portion that engages with a part of the frame body on the inner surface of the bottomed case, the notebook may be particularly subjected to vibration or drop impact. It is useful for prismatic lithium-ion secondary batteries used in consumer electronic devices such as personal computers and mobile phones.

Schematic cross-sectional view of the main part of the battery showing the configuration of the frame and the bottomed case of Example 1 of the present invention Schematic sectional view of the main part of the battery showing the configuration of the frame and the bottomed case of Example 2 of the present invention Schematic sectional view of the main part of the battery showing the configuration of the frame and the bottomed case of Example 3 of the present invention Schematic sectional view of the main part of the battery showing the configuration of the frame and the bottomed case of Example 4 of the present invention Schematic sectional view of the main part of the battery showing the configuration of the frame and the bottomed case of Example 5 of the present invention Schematic sectional view of the main part of the battery showing the structure of the frame and the bottomed case of Example 6 of the present invention Schematic sectional view of the main part of the battery showing the structure of the frame and the bottomed case of Example 7 of the present invention Schematic sectional view of the main part of the battery showing the configuration of the frame and the bottomed case of Example 8 of the present invention (A) Schematic sectional view of the main part of the battery showing the connection state of the lead terminal and sealing plate of the present invention, (b) The battery showing the insertion state of the sealing plate of the present invention into the bottomed case Schematic cross section Schematic sectional view of the main part of the battery showing the configuration of the frame and bottomed case of the conventional comparative example 1 Exploded perspective view showing the structure of the frame and bottomed case of a prismatic lithium ion secondary battery

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bottomed case 2 Lead terminal 3 Electrode body 4 Frame 4a Hole part 5 Concave part 6 Convex part 7 Sealing body 8 Convex part 9 Concave part 10 Convex part 11 Convex part 12 Convex part 13 Convex part 14 Step part 15 Convex part 16 Step part 17 Stepped part

Claims (7)

A bottomed case in which a strip-like positive electrode plate and a negative electrode plate connected with lead terminals are stacked or spirally wound via a separator and the electrolyte is housed therein, and an opening of the bottomed case A battery in which a frame body for insulating the bottomed case and the lead terminal or the electrode body is disposed between the sealing body and the electrode body,
The battery which provided the engaging part which engages with a part of frame body in the inner surface of the said bottomed case.   The battery according to claim 1, wherein one of the inner side surface of the bottomed case and the outer peripheral edge of the frame body is a concave portion and the other is a convex portion, and the concave and convex portions are fitted as the engaging portion.   The battery according to claim 1, wherein a convex portion is provided on the inner side surface of the bottomed case as the engaging portion, and a lower portion of the convex portion and a part of the outer peripheral edge of the frame body are engaged.   The battery according to claim 3, wherein a convex portion is provided on the inner side surface of the bottomed case as the engaging portion, and a lower portion of the convex portion is engaged with an upper end portion of the outer peripheral edge of the frame body.   The battery as described in any one of Claims 2-4 which provided the convex part of the inner surface of the said bottomed case by the extrusion process.   The battery according to claim 1, wherein a step portion is provided on the inner side surface of the bottomed case as the engaging portion, and a lower portion of the step portion and a part of the outer peripheral edge of the frame body are engaged. The battery according to claim 6, wherein a step portion is provided on the inner side surface of the bottomed case as the engaging portion, and a lower portion of the step portion and an upper end portion of the outer peripheral edge of the frame body are engaged.

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