JP2016103412A - Square secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a square secondary battery that prevents an electric collector from being electrically connected to a square armouring can.SOLUTION: A negative electric collector 6 is fixed to a sealing plate 3 through an insulator 11, and a wound electrode body 1 covered with insulation sheets 14 is stored in a square armouring can 2. The negative electric collector 6 has a plate-like terminal connection part 6a, arranged in parallel to the sealing plate 3, to which is connected a negative terminal 7. The insulation member 11 has main body parts 11a positioned above the terminal connection part 6a and peripheral edge ribs 11b provided at peripheral edges of the main body parts 11a. Upper ends of the insulation sheets 14 are positioned above lower faces of the main body parts 11a and do not contact the sealing plate 3.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a prismatic secondary battery in which a current collector is fixed to a sealing plate via an insulating member.

  Alkaline secondary batteries and non-aqueous electrolyte secondary batteries are used as power sources for driving electric vehicles (EV) and hybrid electric vehicles (HEV, PHEV). When these secondary batteries are used as in-vehicle batteries such as EVs, HEVs, PHEVs, etc., high capacity or high output characteristics are required, so a large number of secondary batteries are used as assembled batteries connected in series or in parallel. Is done. For this reason, prismatic secondary batteries are often used as in-vehicle batteries from the viewpoint of space efficiency.

  In these prismatic secondary batteries, a battery case is formed by a metal outer can having an opening and a sealing plate for sealing the opening. In the battery case, an electrode body composed of a positive electrode plate, a negative electrode plate, and a separator is housed together with an electrolytic solution. A positive electrode terminal and a negative electrode terminal are fixed to the sealing plate. The positive electrode terminal is electrically connected to the positive electrode plate via the positive electrode current collector, and the negative electrode terminal is electrically connected to the negative electrode plate via the negative electrode current collector.

  When the battery case is configured to have no polarity of either the positive electrode or the negative electrode, an insulating gasket is disposed between the positive electrode terminal and the sealing plate, and an insulating member is disposed between the positive electrode current collector and the sealing plate. The terminals and the positive electrode current collector are electrically insulated from the sealing plate. An insulating gasket is disposed between the negative electrode terminal and the sealing plate, an insulating member is disposed between the negative electrode current collector and the sealing plate, and the negative electrode terminal, negative electrode current collector and the sealing plate are electrically insulated from each other. .

  When the battery case has a negative polarity, an insulating gasket is disposed between the positive terminal and the sealing plate, an insulating member is disposed between the positive current collector and the sealing plate, and the positive terminal and the positive current collector. And the sealing plate are electrically insulated from each other. Then, a negative electrode terminal or a negative electrode current collector is connected to the sealing plate. When the battery case has a positive polarity, an insulating gasket is disposed between the negative terminal and the sealing plate, an insulating member is disposed between the negative current collector and the sealing plate, and the negative terminal and the negative current collector are disposed. The electric body and the sealing plate are electrically insulated from each other. A positive electrode terminal or a positive electrode current collector is connected to the sealing plate.

  As the insulating member disposed between the current collector and the sealing plate in these prismatic secondary batteries, a flat insulating member or a peripheral edge of the flat main body as disclosed in Patent Documents 1 and 2 below. An insulating member provided with a rib has been proposed. When using an insulating member provided with a peripheral rib on the peripheral edge of the flat plate-shaped main body portion, the peripheral rib abuts on the side surface of the plate-like terminal connecting portion arranged in parallel to the sealing plate in the current collector, It is possible to suppress the movement of the terminal connecting portion in the rotational direction, and it is possible to prevent damage and breakage of the connecting portion between the current collector and the terminal. As disclosed in Patent Document 3 below, this rib need not be provided in an annular shape, and a notch may be formed in part.

  In these prismatic secondary batteries, as disclosed in Patent Documents 4 and 5 below, the electrode body is housed in an outer can in a state covered with an insulating sheet, and the electrode body and the outer casing are covered by the insulating sheet. The can is prevented from touching.

JP 2010-212240 A JP 2010-198946 A US Patent Application Publication No. 2014/0023913 JP 2007-226989 A JP 2010-157451 A

  FIG. 6 is a view of the sealing plate 31 constituting the rectangular secondary battery as seen from the battery inner side, and is an enlarged view of the negative electrode terminal 32 side. The metal sealing plate 31 is welded to the rectangular outer can 33 so as to seal the opening of the metal rectangular outer can 33. A negative electrode terminal 32 and a negative electrode current collector 35 are fixed to the sealing plate 31 via a gasket and an insulating member 34. The negative electrode current collector 35 has a plate-like terminal connection portion 35 a arranged in parallel to the sealing plate 31. The tip of the negative electrode terminal 32 is inserted into a through hole provided in each of the gasket, the sealing plate 31, the insulating member 34, and the terminal connection portion 35a, and the tip is caulked. Thereby, the negative electrode terminal 32, the gasket, the sealing plate 31, the insulating member 34, and the terminal connection part 35a are fixed integrally. The insulating member 34 includes a flat plate-like main body 34 a that is disposed in parallel to the sealing plate 31. The main body 34 a is located above (the sealing plate 31 side) above the upper surface (the surface on the sealing plate 31 side) of the terminal connection portion 35 a of the negative electrode current collector 35. A peripheral rib 34b is formed on the peripheral edge of the main body 34a. A notch 34c is formed in a part of the peripheral rib 34b. In other words, a part where the peripheral rib 34b is not formed is provided on a part of the peripheral edge of the main body part 34a, and this part becomes the notch part 34c. A lead portion 35 b extending toward the electrode body is formed at the end of the terminal connection portion 35 a of the negative electrode current collector 35.

  In the prismatic secondary battery shown in FIG. 6, an elongated conductive foreign material 40 is sandwiched between the terminal connecting portion 35 a and the peripheral rib 34 b, and the negative electrode current collector 35 and the rectangular outer can 33 are interposed via the elongated conductive foreign material 40. May be electrically connected. Such a problem exists not only on the negative electrode side but also on the positive electrode side. When the current collector and the rectangular outer can are electrically connected unintentionally, there is a possibility that problems such as a short circuit between the positive electrode and the negative electrode or corrosion of the rectangular outer can occur. It should be noted that the elongated conductive foreign matter adheres to the electrode body or the like during battery manufacture, and when the electrolytic solution is poured into the rectangular outer can, the foreign matter is flowed by the electrolytic solution, and the terminal connection portion of the current collector and the insulating member It is considered to be sandwiched between the peripheral rib insulating members. In addition, there exists a possibility that an electroconductive foreign material may be pinched | interposed between the terminal connection part of an electrical power collector, and the main-body part of an insulating member.

  The present invention solves such a problem, and an object of the present invention is to provide a prismatic secondary battery that reliably prevents the current collector and the prismatic outer can from being electrically connected in an unintended state. .

In order to achieve the above object, the prismatic secondary battery of the present invention provides:
A metal square outer can having an opening above,
A metal sealing plate for sealing the opening;
An electrode body housed in the rectangular outer can;
A current collector electrically connected to the electrode plate of the electrode body;
A terminal electrically connected to the current collector;
An insulating member disposed between the sealing plate and the current collector;
A gasket disposed between the sealing plate and the terminal;
A prismatic secondary battery comprising an insulating sheet that covers the electrode body and is disposed between the electrode body and the prismatic outer can,
The sealing plate is welded to the square outer can,
The current collector has a plate-like terminal connecting portion connected to the terminal and arranged in parallel to the sealing plate, and a lead portion extending from the end of the terminal connecting portion toward the electrode body,
The insulating member is located above the upper surface of the terminal connecting portion and is disposed in parallel with the sealing plate between the sealing plate and the terminal connecting portion; and Having a peripheral rib formed on the periphery,
The upper end of the insulating sheet is located above the lower surface of the main body,
The upper end portion of the insulating sheet is not in contact with the sealing plate.

  According to the said structure, it becomes the structure by which an insulating sheet is arrange | positioned between a collector and a square-shaped exterior can, and a collector and a square-shaped exterior can do not directly oppose without interposing an insulating sheet. Therefore, even when a thin and long conductive foreign object is sandwiched between the current collector and the peripheral rib of the insulating member, the current collector and the rectangular outer can are electrically connected via the thin and long foreign object. It can be surely prevented. Further, since the upper end portion of the insulating sheet is not in contact with the sealing plate, the welding operation is not hindered by the insulating sheet when the sealing plate is welded to the rectangular outer can. Moreover, there is no possibility that the insulating sheet is deformed by contact with the sealing plate. In addition, it is preferable that the upper end part of an insulating sheet is located 0.1 mm or more below the lower surface of a sealing board.

  Moreover, it is preferable that the shortest distance between the side surface of the main body and the inner surface of the rectangular outer can is less than 1.0 mm. In such a configuration, the present invention is particularly effective.

  Further, the lead portion has a boundary vicinity portion located in the vicinity of the boundary portion between the terminal connection portion and the lead portion, and the boundary vicinity portion is formed between the terminal connection portion and the lead portion in the lead portion. It is a part located within 3 mm downward from the boundary part, and it is preferable that the shortest distance between the boundary vicinity part and the rectangular outer can is less than 1.2 mm. In such a configuration, the present invention is particularly effective.

  The rectangular secondary battery is preferably a lithium ion secondary battery, and the rectangular outer can is preferably made of aluminum or an aluminum alloy. In such a configuration, the present invention is particularly effective.

  Moreover, the notch part may be partially formed in the peripheral rib. The notch is preferably formed at a position corresponding to the boundary between the terminal connection portion and the lead portion. With such a configuration, it is possible to prevent the lead portion from coming into contact with the peripheral rib when the current collector is arranged on the insulating member and hindering the arrangement work. At this time, it is preferable to make the width of the notch portion larger than the width of the lead portion. For example, it is preferable that a gap of 0.3 mm or more is formed between each side of the lead portion and the peripheral rib. However, the notch is not an essential configuration in the present invention.

(A) is sectional drawing of the square secondary battery which concerns on embodiment, (B) is sectional drawing along the IB-IB line of (A). It is the sealing board used for the square secondary battery which concerns on embodiment, and is the top view which looked at the state in which the collector was attached from the back surface side. FIG. 3 is an enlarged view of the negative electrode current collector side in FIG. 2. FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. 3. FIG. 5 is a cross-sectional view taken along the line VV in FIG. 3. It is the sealing plate of the square secondary battery which concerns on a prior art, and is the top view which looked at the state in which the collector was attached from the back surface side. It is a figure corresponding to FIG. 4 of the square secondary battery which concerns on a comparative example. FIG. 5 is an enlarged view of a portion X in FIG. 4.

  Embodiments of the present invention will be described below in detail with reference to the drawings. First, the structure of the square secondary battery 20 according to the embodiment will be described with reference to FIG.

  As shown in FIG. 1, the rectangular secondary battery 20 includes a metal rectangular outer can 2 having an opening on the upper side and a metal sealing plate 3 that seals the opening. The rectangular outer can 2 and the sealing plate 3 constitute a battery case. In the rectangular secondary battery 20, a flat wound electrode body 1 in which a positive electrode plate and a negative electrode plate are wound via a separator (both not shown) is accommodated inside a rectangular outer can 2, and a sealing plate 3 The square outer can 2 is hermetically sealed. The rectangular outer can 2 and the sealing plate 3 are made of, for example, aluminum or an aluminum alloy. The prismatic secondary battery 20 includes a negative electrode current collector 6 connected to the negative electrode plate and a positive electrode current collector connected to the positive electrode plate as current collectors electrically connected to the electrode plate of the wound electrode body 1. 8 is provided. The wound electrode body 1 includes a negative electrode core exposed portion 4 and a positive electrode core exposed portion 5 that are not coated with a positive electrode mixture and a negative electrode mixture, respectively, at both ends in the winding axis direction. The negative electrode core exposed portion 4 is connected to the negative electrode terminal 7 via a negative electrode current collector 6 made of, for example, copper or a copper alloy. The positive electrode core exposed portion 5 is connected to the positive electrode terminal 9 via a positive electrode current collector 8 made of, for example, aluminum or aluminum alloy. Note that the negative electrode terminal 7 electrically connected to the negative electrode current collector 6 and the positive electrode terminal 9 electrically connected to the positive electrode current collector 8 are both projected on the sealing plate 3. The negative electrode current collector 6 is welded to the negative electrode core exposed portion 4, and a negative electrode current collector receiving component is provided on the surface of the negative electrode core exposed portion 4 opposite to the side where the negative electrode current collector 6 is disposed. Has been placed. The positive electrode current collector 8 is welded to the positive electrode core exposed portion 5, and the positive electrode current collector receiving component 8 d is provided on the surface of the positive electrode core exposed portion 5 opposite to the side where the positive electrode current collector 8 is disposed. Is arranged.

  The negative electrode terminal 7 and the negative electrode current collector 6 are fixed to the sealing plate 3 via a gasket 10 and an insulating member 11, respectively. The positive electrode terminal 9 and the positive electrode current collector 8 are fixed to the sealing plate 3 via a gasket 12 and an insulating member 13, respectively. The gaskets 10 and 12 are respectively disposed between the sealing plate 3 and each terminal, and the insulating members 11 and 13 are respectively disposed between the sealing plate 3 and each current collector. The negative terminal 7 and the positive terminal 9 have flanges 7a and 9a, respectively. The wound electrode body 1 is accommodated in the rectangular outer can 2 while being covered with the insulating sheet 14. The insulating sheet 14 covers the wound electrode body 1 and is disposed between the wound electrode body 1 and the rectangular outer can 2. The sealing plate 3 is welded and connected to the opening edge of the rectangular outer can 2 by laser welding or the like. The sealing plate 3 has an electrolyte injection hole 15, and the electrolyte injection hole 15 is sealed by a sealing plug 16 after the injection. The sealing plate 3 is formed with a gas discharge valve 17 for discharging gas when the pressure inside the battery becomes high.

Next, a method for manufacturing the wound electrode body 1 will be described. A positive electrode mixture containing, for example, lithium cobaltate (LiCoO ₂ ) as a positive electrode active material is uniformly applied to both surfaces of a 15 μm-thick rectangular aluminum foil that is a positive electrode core to form a positive electrode active material mixture layer. A positive electrode plate was produced by forming a positive electrode core exposed portion having a predetermined width in which the positive electrode active material mixture was not applied to one end portion in the short side direction. Also. A negative electrode mixture containing, for example, natural graphite powder as a negative electrode active material is uniformly applied to both sides of a rectangular copper foil having a thickness of 8 μm, which is a negative electrode core, to form a negative electrode active material mixture layer. A negative electrode plate was produced by forming a negative positive electrode core exposed portion having a predetermined width on which the negative electrode active material mixture was not applied at one end of the negative electrode plate.

  The polyethylene porous separator is obtained by shifting the positive electrode core exposed portion of the positive electrode plate obtained by the above method and the negative electrode core exposed portion of the negative electrode plate so as not to overlap the active material mixture layer of the opposing electrode. In the embodiment, a negative electrode core exposed portion 4 in which a plurality of copper foils are laminated at both ends and a positive electrode core exposed portion 5 in which a plurality of aluminum foils are laminated are formed. A flat wound electrode body 1 used in the form was produced.

  Next, the attachment state to the sealing plate 3 of the negative electrode collector 6 and the positive electrode collector 8 is demonstrated using FIGS.

  As shown in FIGS. 1 and 2, on one end side in the longitudinal direction of the sealing plate 3, the gasket 10 is disposed on the battery outer side of the sealing plate 3, and the insulating member 11 is disposed on the battery inner side of the sealing plate 3. . The negative electrode terminal 7 is disposed on the gasket 10, and the negative electrode current collector 6 is disposed on the lower surface of the insulating member 11. And the negative electrode terminal 7, the gasket 10, the sealing board 3, the insulating member 11, and the negative electrode collector 6 are being fixed integrally. The negative electrode current collector 6 is arranged in parallel to the sealing plate 3 and is connected to the negative electrode terminal 7. The negative electrode current collector 6 extends from the end of the terminal connection portion 6 a toward the wound electrode body 1. The lead part 6b and the connection part 6c which is located in the front end side of the lead part 6b and is connected to the negative electrode core exposed part 4 are provided.

  On the other end side in the longitudinal direction of the sealing plate 3, a gasket 12 is disposed on the battery outer side of the sealing plate 3, and an insulating member 13 is disposed on the battery inner side of the sealing plate 3. The positive electrode terminal 9 is disposed on the gasket 12, and the positive electrode current collector 8 is disposed on the lower surface of the insulating member 13. The positive electrode terminal 9, the gasket 12, the sealing plate 3, the insulating member 13, and the positive electrode current collector 8 are integrally fixed. The positive electrode current collector 8 is arranged in parallel to the sealing plate 3 and is connected to the positive electrode terminal 9. The positive electrode current collector 8 extends from the end of the terminal connection portion 8 a toward the wound electrode body 1. A lead portion 8b and a connection portion 8c that is located on the tip side of the lead portion 8b and connected to the positive electrode core body exposed portion 5 are provided.

  Here, the configuration in the vicinity of the negative electrode terminal 7 and the vicinity of the positive electrode terminal 9 will be described. However, the materials of the current collector and the terminal are different between the negative electrode side and the positive electrode side, and the structure is substantially symmetrical. Other than that, it has the same configuration. Therefore, in the following description, the negative electrode side will be described as an example, and the detailed description of the positive electrode side will be omitted.

  As shown in FIG. 3, the insulating member 11 includes a plate-like main body portion 11 a arranged in parallel to the sealing plate 3 and a peripheral rib 11 b provided on the peripheral edge of the main body portion 11 a. The main body part 11 a is disposed between the terminal connection part 6 a of the negative electrode current collector 6 and the sealing plate 3. The main body 11 a is located above (on the sealing plate 3 side) the upper surface (the surface on the sealing plate 3 side) of the terminal connection portion 6 a of the negative electrode current collector 6. The peripheral rib 11 b is located between the side surface of the terminal connection portion 6 a of the negative electrode current collector 6 and the inner surface of the rectangular outer can 2. The peripheral rib 11b plays a role of suppressing movement of the terminal connecting portion 6a in the rotational direction. The peripheral rib 11b is provided with a notch portion 11c. In other words, the peripheral edge of the main body portion 11a is provided with a portion where the peripheral rib 11b is not formed in part.

  The notch portion 11 c is provided in a portion corresponding to the boundary portion between the terminal connection portion 6 a and the lead portion 6 b in the negative electrode current collector 6. When the notch portion 11 c is provided at this position, the peripheral rib 11 b serves as the lead portion of the negative electrode current collector 6 when the terminal connection portion 6 a of the negative electrode current collector 6 is disposed on the main body portion 11 a of the insulating member 11. It is possible to prevent the arrangement work from interfering with 6b. In the width direction of the main body portion 11a, the notch portion 11c can also be provided in a portion of the negative electrode current collector 6 that faces the portion corresponding to the boundary portion between the terminal connection portion 6a and the lead portion 6b.

  The negative electrode current collector 6 and the positive electrode current collector 8 are preferably fixedly connected to the sealing plate 3 before being connected to the negative electrode core body exposed portion 4 and the positive electrode core body exposed portion 5, respectively. The fixed connection method is as follows. First, the gasket 10 is disposed on the front surface side of the sealing plate 3, and the insulating member 11 and the terminal connection portion 6 a of the negative electrode current collector 6 are disposed on the back surface side of the sealing plate 3. Then, the negative electrode terminal 7 is inserted into the through hole of the gasket 10, the through hole of the sealing plate 3, the through hole of the insulating member 11, and the through hole of the terminal connection 6 a, and the tip of the negative electrode terminal 7 is fixed by crimping. In addition, you may laser-weld the boundary part of the negative electrode terminal 7 and the terminal connection part 6a. The positive electrode side is also fixed in the same manner as the negative electrode side.

  The wound electrode body 1 connected to the sealing plate 3 via the negative electrode current collector 6 and the positive electrode current collector 8 is made of a resin, for example, polypropylene, which is formed by bending the periphery except the upper surface into a bag shape or a box shape. It is inserted into the rectangular outer can 2 while being wrapped with the sheet 14. Thus, the insulating sheet 14 is positioned between the bottom surface of the rectangular outer can 2 and the wound electrode body 1 and between the four side surfaces of the rectangular outer can 2 and the wound electrode body 1, and is wound by the insulating sheet 14. The electrode body 1 and the rectangular outer can 2 are electrically insulated. Thereafter, the contact portion between the rectangular outer can 2 and the sealing plate 3 is laser-welded. Then, a nonaqueous electrolytic solution is injected from the electrolytic solution injection hole 15 formed in the sealing plate 3, and the electrolytic solution injection hole 15 is sealed by the sealing plug 16.

  As shown in FIGS. 4 and 5, in the rectangular secondary battery 20, the box-shaped insulating sheet 14 has an opening on the sealing plate 3 side, and the upper end of the insulating sheet 14 is in the vicinity of the sealing plate 3. It extends to.

  In the rectangular secondary battery 20, the position of the upper end portion of the insulating sheet 14 is located above (the sealing plate 3 side) above the lower surface (surface on the terminal connection portion 6 a side) of the main body portion 11 a of the insulating member 11. For this reason, the insulating sheet 14 is necessarily disposed between the negative electrode current collector 6 and the rectangular outer can 2, and there is no portion where the negative electrode current collector 6 and the rectangular outer can 2 directly face each other. Therefore, even if an elongated conductive foreign object is sandwiched between the terminal connecting portion 6a of the negative electrode current collector 6 and the insulating member 11, the negative electrode current collector 6 and the rectangular outer can 2 are connected via the conductive foreign object. It is possible to reliably prevent the gaps from being electrically connected.

  In addition, as shown in FIG. 7, when the position of the upper end part of the insulating sheet 14 is located below the lower surface of the main body part 11a of the insulating member 11 (on the side of the wound electrode body 1), an elongated conductive foreign matter Since there is a possibility that the negative electrode current collector 6 and the rectangular outer can 2 are electrically connected via 40, the problem to be solved by the present invention cannot be solved.

  In the rectangular secondary battery 20 of the embodiment, the upper end portion of the insulating sheet 14 is not in contact with the sealing plate 3. For this reason, when the sealing plate 3 and the rectangular outer can 2 are welded and connected by laser welding or the like, the insulating sheet 14 does not hinder the welding operation. The upper end portion of the insulating sheet 14 is preferably separated from the lower surface of the sealing plate 3 by 0.1 mm or more.

  FIG. 8 is an enlarged view of a portion X in FIG. As shown in FIG. 8, the upper end portion of the insulating sheet 14 is connected to the insulating member 11 in a rectangular secondary battery in which the shortest distance D1 between the side surface of the main body 11 a of the insulating member 11 and the inner surface of the rectangular outer can 2 is less than 1.0 mm. It is particularly effective to apply a configuration (hereinafter referred to as “the above configuration”) arranged above the lower surface of the main body 11a.

  The above configuration is particularly effective when applied to a prismatic secondary battery in which the shortest distance D2 between the boundary vicinity portion 6e of the lead portion 6b and the prismatic outer can 2 is less than 1.2 mm. Here, the boundary vicinity portion 6e is a portion in the lead portion 6b that is located within 3 mm downward from the boundary portion 6d between the terminal connection portion 6a and the lead portion 6b.

  As shown in FIG. 8, the negative electrode current collector 6 has a boundary portion 6d between the terminal connection portion 6a and the lead portion 6b. The lead portion 6b has a boundary vicinity portion 6e located within 3 mm below the boundary portion 6d. In such a rectangular secondary battery, when the shortest distance D2 between the boundary vicinity 6e and the rectangular outer can 2 is less than 1.2 mm, the problem to be solved by the present invention is likely to occur. Therefore, it is more effective to apply the above configuration to such a square secondary battery.

  Further, in order to more reliably prevent the current collector and the rectangular outer can from being electrically connected via the conductive foreign matter, the distance between the insulating sheet 14 and the insulating member 11 is 0.1 mm or more. It is preferable to arrange in.

  Further, the upper end portion of the insulating sheet 14 may be positioned above the upper surface of the main body portion 11a. In order to obtain such a configuration, a concave portion is provided at a position corresponding to the upper end portion of the insulating sheet 14 on the inner surface side of the sealing plate 3 (for example, the shape as in FIG. 5 of Patent Document 3). The upper end of the insulating sheet 14 may be positioned inside.

  The said structure should just be applied to at least one of the negative electrode side and the positive electrode side. However, the above configuration is preferably applied to the negative electrode side. When the prismatic secondary battery is a lithium ion secondary battery and the prismatic outer can is made of aluminum or an aluminum alloy, the prismatic outer can may be corroded when the negative electrode current collector and the prismatic outer can are electrically connected. is there. Therefore, when the above configuration is applied to the negative electrode side, corrosion of the rectangular outer can can be reliably prevented. In addition, when the rectangular outer can has a positive polarity, a short circuit between the positive and negative electrodes can be reliably prevented by applying the above configuration to the negative electrode side.

  In the above embodiment, the wound electrode body is exemplified as the electrode body housed in the rectangular outer can, but the electrode body may be a laminated electrode body.

  The rectangular outer can may be made of metal, and the material is not limited. However, the rectangular outer can is preferably made of aluminum or an aluminum alloy. The insulating sheet only needs to be electrically insulating, and a polyolefin sheet or the like can be used. The insulating member only needs to be electrically insulating, and is preferably a resin member.

DESCRIPTION OF SYMBOLS 1 ... Winding electrode body 2 ... Rectangular outer can 3 ... Sealing plate 4 ... Negative electrode core exposure part 5 ... Positive electrode core exposure part 6 ... Negative electrode collector 6a ... Terminal connection part 6b ... Lead part 6c ... Connection part 6d ... Boundary part 6e ... Boundary vicinity part 7 ... Negative electrode terminal 7a ... ridge part 8 ... Positive electrode current collector 8a ... Terminal connection part 8b ... Lead part 8c ... Connection part 8d ... Positive electrode current collector receiving component 9 ... Positive electrode terminal 9a ... Eaves part 10 and 12 ... Gaskets 11 and 13 ... Insulating member 11a ... Main body part 11b ... Rim edge rib 11c ... Notch part 14 ... Insulating sheet 15 ... Electrolyte injection hole 16 ... Sealing plug 17 ... Gas discharge valve 20 ... square secondary battery 31 ... sealing plate 32 ... negative electrode terminal 33 ... square outer can 34 ... insulating member 34a ... main body 34b · Peripheral ribs 35 ... negative electrode current collector 35a ... terminal connecting portions 35b ... lead portion 40 ... conductive foreign substance

Claims (4)

A metal square outer can having an opening above,
A metal sealing plate for sealing the opening;
An electrode body housed in the rectangular outer can;
A current collector electrically connected to the electrode plate of the electrode body;
A terminal electrically connected to the current collector;
An insulating member disposed between the sealing plate and the current collector;
A gasket disposed between the sealing plate and the terminal;
A prismatic secondary battery comprising an insulating sheet that covers the electrode body and is disposed between the electrode body and the prismatic outer can,
The sealing plate is welded to the square outer can,
The current collector has a plate-like terminal connecting portion connected to the terminal and arranged in parallel to the sealing plate, and a lead portion extending from the end of the terminal connecting portion toward the electrode body,
The insulating member is located above the upper surface of the terminal connecting portion and is disposed in parallel with the sealing plate between the sealing plate and the terminal connecting portion; and Having a peripheral rib formed on the periphery,
The upper end of the insulating sheet is located above the lower surface of the main body,
A rectangular secondary battery in which an upper end portion of the insulating sheet is not in contact with the sealing plate.   The prismatic secondary battery according to claim 1, wherein a shortest distance between a side surface of the main body portion and an inner surface of the rectangular outer can is less than 1.0 mm. The lead portion has a boundary vicinity portion located in the vicinity of a boundary portion between the terminal connection portion and the lead portion,
The boundary vicinity portion is a portion located within 3 mm downward from the boundary portion between the terminal connection portion and the lead portion in the lead portion,
The prismatic secondary battery according to claim 1 or 2, wherein a shortest distance between the boundary vicinity and the prismatic outer can is less than 1.2 mm.   The prismatic secondary battery according to any one of claims 1 to 3, wherein the prismatic secondary battery is a lithium ion secondary battery, and the prismatic outer can is made of aluminum or an aluminum alloy.

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