JP2013093225A - Storage element, electric cell, and battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To abolish a work of fixing an elastic body to an exterior body after a power generation element is housed in the exterior body to absorb the swelling of a storage element.SOLUTION: An electric cell B includes a power generation element 10 having an electrode plate where an active material layer is formed on a metal foil surface, an external body 30 for housing the power generation element 10, and a spacer 40 received between the power generation element 10 and the external body 30. A swollen part 33 for receiving and holding the spacer 40 therein is formed in the external body 30. According to the arrangement, swelling of the electric cell B can be absorbed by the spacer 40 when a plurality of electric cells B are arranged side by side. Since it is simply required to house the power generation element 10 in the external body 30 where the spacer 40 has been held on the swollen part 33 previously, the work of fixing the spacer 40 to the exterior body 30 after the power generation element 10 is housed in the exterior body 30 can be abolished.

Description

  The present invention relates to a power storage element, a single battery, and an assembled battery.

  Conventionally, an electrochemical device such as a battery or an electric double layer capacitor in which a power generation element having an electrode plate having an active material layer formed on the surface of a metal foil is housed in an exterior body is known (for example, the following patent document) 1). A resin plate made of resin is fixed to the center of the side surface of the exterior body by adhesion. In this case, when a plurality of electrochemical devices are arranged side by side, a predetermined gap is formed between the adjacent electrochemical devices, so that each electrochemical device can be cooled.

JP 2002-245992 A

  However, in the above electrochemical device, after the power generation element is accommodated in the exterior body, it is necessary to fix the resin plate to the side surface of the exterior body. Although the above-described electrochemical device uses a resin plate for the purpose of cooling, even when an elastic body is used to absorb the swelling of the storage element, a procedure for fixing the elastic body to the exterior body Is the same.

  The present invention has been completed based on the above-described circumstances, and eliminates the work of fixing the elastic body to the exterior body after the power generation element is accommodated in the exterior body in absorbing the swelling of the storage element. The purpose is to do.

An electricity storage device of the present invention includes a power generation element, an exterior body that houses the power generation element, and an elastic body that is housed between the power generation element and the exterior body, and the exterior body houses the elastic body inside. It is characterized in that it has a configuration in which a concave portion to be held is formed.
In addition, the present invention may be applied to the above-described power storage element in a unit cell, or may be applied to a battery pack in which a plurality of unit cells are arranged side by side.

  According to such a configuration, when a plurality of power storage elements are arranged side by side, the swelling of the power storage elements can be absorbed by the elastic body. Here, when manufacturing the electricity storage element, the elastic body can be accommodated and held in the recess, and therefore, it is only necessary to accommodate the power generation element in the exterior body in which the elastic body is previously held. Therefore, the work of fixing the elastic body to the exterior body after the power generation element is accommodated in the exterior body can be eliminated.

The following configuration is preferable as an embodiment of the present invention.
The exterior body may be formed by molding a resin sheet into a bag shape, and the recess may be formed by bulging a part of the exterior body away from the power generation element.
According to such a structure, a recessed part can be formed when a resin-made sheet | seat is shape | molded in a bag shape and an exterior body is formed.

The recess may have a shape whose inner side is wider than the opening, and the elastic body may be accommodated in the recess.
According to such a configuration, since the inner side of the recess is formed to be wider than the opening, the elastic body can be fixed to the exterior body only by housing the elastic body inside the recess.

The elastic body has an engaging portion that engages with the opening edge of the opening from the inside, and the engaging portion may be formed to extend in the circumferential direction of the elastic body. .
According to such a configuration, since the engaging portion extends in the circumferential direction of the elastic body, the engaging portion can be engaged with the opening edge of the opening in a wide range. Therefore, the holding force of the elastic body with respect to the exterior body can be improved.

The engaging portion may be formed over the entire circumference of the elastic body, while the opening edge portion of the opening may be formed so as to protrude toward the center of the opening over the entire circumference. .
According to such a structure, since the engaging part and the opening edge part of the opening part are each formed over the perimeter, these can be engaged over a perimeter. Therefore, the holding force of the elastic body with respect to the exterior body can be further improved.

An electrode terminal for inputting and outputting electric power may be provided, and the elastic body may be configured to face a surface adjacent to the surface on which the electrode terminal is disposed, of the outer surface of the power generation element.
According to such a configuration, when a plurality of power storage elements are arranged side by side, the surfaces on which the electrode terminals are disposed can be installed in the same direction (for example, upward). It becomes easy to connect.

  According to the present invention, the work of fixing the elastic body to the exterior body after the power generation element is accommodated in the exterior body can be eliminated when absorbing the swelling of the electricity storage element.

Single cell perspective view Front view of battery pack Plan view of battery pack Sectional view of the internal structure of the exterior body and elastic body as seen from the front Sectional view of the internal structure of the exterior body and elastic body as seen from above 4 is an enlarged cross-sectional view of the main part Plan view of exterior body in unfolded state Disassembled perspective view of the battery body Disassembled perspective view of single cell The principal part expanded sectional view which shows the periphery structure of the elastic body in other embodiment

<Embodiment>
An embodiment of the present invention will be described with reference to the drawings of FIGS. The storage element in the present embodiment is a large lithium ion battery (hereinafter simply referred to as a single battery B) which is a kind of non-aqueous electrolyte secondary battery mounted on a vehicle such as an electric vehicle or a hybrid vehicle. As shown in FIG. 9, the unit cell B includes a battery body B <b> 1, an exterior body 30, and a spacer 40. The battery body B1 is housed in the exterior body 30 together with the spacer 40. The battery body B1 is a prismatic battery in which the flat power generation element 10 is accommodated in the rectangular cell case 28 shown in FIG. 8, and the cell case 28 is filled with an electrolyte. Hereinafter, in each component member, the upper side of FIG.

  As shown in FIG. 8, the power generation element 10 is obtained by winding a stack of a positive electrode plate and a negative electrode plate with a separator sandwiched around a core 11 having a rectangular shape made of polyethylene. The positive electrode plate is a positive electrode in which a positive electrode active material layer is formed on the surface of a strip-shaped aluminum foil, and the positive electrode active material layer is not formed on one edge extending in the longitudinal direction, and the aluminum foil is exposed. A current collector foil 12 is formed. The negative electrode plate has a negative electrode active material layer formed on the surface of a strip-shaped copper foil. The negative electrode active material layer is not formed on one edge extending in the longitudinal direction, and the copper foil is exposed. The negative electrode current collector foil 13 is formed.

  The positive electrode plate and the negative electrode plate are arranged in such a direction that the positive electrode current collector foil 12 and the negative electrode current collector foil 13 are arranged on the opposite side, and the positive electrode current collector foil 12 is arranged outside the separator and the negative electrode plate. The foil 13 is overlapped and wound so as to be disposed outside the separator and the positive electrode plate. Thereby, only the positive electrode current collector foil 12 is laminated and protruded at one end side (positive electrode side) in the width direction of the power generation element 10, and only the negative electrode current collector foil 13 is provided at the other end side (negative electrode side). It is stacked and protruded.

  Each of the positive electrode current collector foil 12 and the negative electrode current collector foil 13 is wound in an oval shape that is long in the vertical direction, and side portions 12A and 13A that extend linearly in the vertical direction are positive electrode current collectors 24 described later. Alternatively, the welded portion is welded to the negative electrode current collector 25. A positive electrode current collector 24 connected to the positive electrode terminal 22 is connected to the positive electrode current collector foil 12, and a negative electrode current collector 25 connected to the negative electrode terminal 23 is connected to the negative electrode current collector foil 13. Each of the current collectors 24 and 25 is made of a metal plate having a sufficient thickness so that a large current capacity can be obtained. The positive electrode current collector 24 is made of, for example, an aluminum alloy plate, and the negative electrode current collector. 25 consists of a copper plate alloy plate, for example. Further, the terminals 22 and 23 are integrally assembled by a non-conductive lid 21.

  The positive electrode current collector 24 includes a pair of leg portions 24A and 24A connected to the side surface portions 12A and 12A of the positive electrode current collector foil 12. On the other hand, the negative electrode current collector 25 includes a pair of leg portions 25A and 25A connected to the side surface portions 13A and 13A of the negative electrode current collector foil 13. The leg portions 24A and 24A of the positive electrode current collector 24 are arranged in such a direction that the plate surfaces face each other, and have an elongated shape and extend in the vertical direction. Similarly, the leg portions 25A and 25A of the negative electrode current collector 25 are also arranged in such a direction that the plate surfaces face each other, and have an elongated shape and extend in the vertical direction. Each leg portion 24A, 25A is welded by welding means such as ultrasonic welding in a state in which the leg portions 24A, 25A are in close contact with the side surface portions 12A, 13A of the current collector foils 12, 13 by a plurality of clips 27. The portions 12A and 13A are connected to be conductive.

  As shown in FIG. 9, the exterior body 30 includes a bag-like container body 31 whose upper surface side is open. The container body 31 is made of an insulating resin sheet (for example, an insulating tube), and the sheet has a property of contracting by heat.

  A positive electrode terminal 22 and a negative electrode terminal 23 for inputting and outputting power pass through the lid body 21 and protrude upward. A bulging portion 33 is formed at the center of the side surface 32 of the container body 31. The bulging portion 33 is formed by vacuum forming a sheet so as to bulge a part of the resin sheet constituting the container body 31. For example, as shown in FIG. 7, a bulging portion 33 is formed in advance on one side surface 32 of a sheet-like container body 31 in an unfolded state, and is bent so that the side surfaces 32 and 32 face each other. In addition, the joint portions 36, 36 respectively disposed on both sides of the side surface 32 are thermally welded to form the bag-like container body 31.

  As shown in FIGS. 2 and 3, each unit cell B is arranged side by side so that the side surfaces 32 face each other, and the terminals 22 and 23 of the plurality of unit cells B are connected in series or in parallel. As a result, the assembled battery AB is configured. The bulging portion 33 is provided on either one of the two side surfaces 32, 32 of each unit cell B, and each unit cell B is disposed so that the bulge unit 33 of each unit cell B faces the same direction. Has been. Therefore, the adjacent unit cells B are arranged such that the side surfaces 32 and 32 facing each other are spaced apart from each other and are in contact with each other at the bulging portion 33.

  As shown in detail in FIG. 6, the bulging portion 33 has a form opening to the power generation element 10 side, and is formed by bulging a part of the side surface 32 in a direction away from the power generation element 10. In other words, the bulging portion 33 has an opening 34 close to the power generation element 10 and has a shape (a dovetail shape) that is wider on the inner side than the opening 34, and the opening edge 34A of the opening 34 is entirely formed. It is formed so as to protrude to the center side of the opening 34 over the circumference. A back wall 35 disposed on the opposite side of the bulging portion 33 from the opening 34 is planar. As shown in FIG. 2 or 3, the back wall 35 comes into surface contact with the side surface 32 of the container body 31 adjacent to the container body 31 provided with the back wall 35.

  A spacer 40 made of an elastic member such as rubber is accommodated in the bulging portion 33. The spacer 40 has a substantially square block shape, and the outer surface 42 disposed on the back wall 35 side is slightly larger than the inner surface 41 disposed on the opening 34 side of the bulging portion 33. Is formed. Further, the circumferential surface 43 disposed over the entire circumference between the inner side surface 41 and the outer side surface 42 of the spacer 40 is directed from the back wall 35 side to the opening 34 side as shown in FIGS. 4 and 5. The tapered inclined surface is inclined so as to approach the axial center side of the spacer 40 (the axis side connecting the center of the inner side surface 41 and the center of the outer side surface 42).

  The outer surface 42 of the spacer 40 is formed slightly larger than the opening 34 of the bulging portion 33, and the inner surface 41 of the spacer 40 is formed slightly smaller than the opening 34 of the bulging portion 33. Yes. Further, when the outer surface 42 of the spacer 40 is in contact with the inner wall 35 of the bulging portion 33, the inner side surface 41 of the spacer 40 is disposed in the opening 34 of the bulging portion 33 and contacts the side surface of the power generation element 10. It is possible to contact. Furthermore, the outer surface 42 and the peripheral surface 43 of the spacer 40 are shaped to substantially conform to the internal shape of the bulging portion 33. Therefore, the spacer 40 is accommodated in the inside of the bulging portion 33 so as to be substantially fitted, and is held inside the bulging portion 33 by the peripheral surface 43 engaging with the opening edge portion 34A of the opening portion 34 from the inside. Has been. As a result, the inner surface 41 of the spacer 40 is held in an arrangement facing the surface (side surface) adjacent to the surface (upper surface) on which the terminals 22 and 23 are disposed, of the outer surface of the power generation element 10.

  The present embodiment is configured as described above, and its operation will be described subsequently. First, a resin sheet is punched into a predetermined shape, and a sheet vacuum forming is performed on the punched sheet to bulge-mold the bulging portion 33 shown in FIG. Here, the spacer 40 is fitted into the bulging portion 33. Since the spacer 40 is a rubber material, the spacer 40 passes through the opening 34 while being elastically deformed, and the spacer 40 is pushed in until the outer surface 42 abuts the back wall 35. Then, the peripheral surface 43 of the spacer 40 engages with the opening edge 34 </ b> A of the opening 34 from the inside, and the spacer 40 is accommodated and held inside the bulging portion 33.

  Next, the side surfaces 32 and 32 of the sheet-like container body 31 are folded so as to enclose the battery body B1, and the joint portions 36 are thermally welded to form the bag-like container body 31. FIG. A cell B shown in FIG. According to such a molding method, it is not necessary to attach the spacer 40 with an adhesive tape or the like after the container body 31 is molded. Therefore, the mounting operation of the spacer 40 is simplified and the productivity can be improved. Moreover, since it is not necessary to use an adhesive tape etc. when affixing the spacer 40 to the container body 31, a component cost can be reduced.

  Thereafter, as shown in FIG. 2, a plurality of single cells B are arranged in parallel at a predetermined interval, and the assembled battery AB is configured by connecting the terminals 22 and 23 in series or in parallel. In the state of the assembled battery AB, the back wall 35 of each bulging portion 33 is in contact with the side surface 32 of the adjacent unit cell B. Here, when charging / discharging is repeatedly performed on each unit cell B, each unit cell B expands. Even in that case, since each spacer 40 absorbs the swelling, the swelling of the assembled battery AB accompanying the expansion of the unit cell B can be regulated.

  Further, when the unit cell B is subjected to strong vibration or impact, the battery body B <b> 1 having a relatively large weight tends to be displaced in the exterior body 30. Then, the battery body B1 comes into contact with the spacer 40, and the spacer 40 is pushed by the battery body B1 and comes into contact with the back wall 35 of the bulging portion 33. Therefore, even when the unit cell B is subjected to strong vibration or impact, it is possible to prevent a situation in which the current collectors 24 and 25 are deformed and the current collector foils 12 and 13 are cracked. High vibration resistance and impact resistance can be realized.

  As described above, in this embodiment, when the plurality of single cells B are arranged side by side, the swelling of each battery body B1 can be absorbed by the spacer 40. Here, when the unit cell B is manufactured, the spacer 40 can be accommodated and held inside the bulging portion 33, so the power generation element 10 is attached to the exterior body 30 in which the spacer 40 is held in advance. All you need is accommodation. Therefore, the work of fixing the spacer 40 to the exterior body 30 after the power generation element 10 is accommodated in the exterior body 30 can be abolished.

  Further, since the bulging portion 33 is formed so as to bulge a part of the container body 31, the bulging portion 33 is formed when the resin sheet is formed into a bag shape to form the container body 31. can do. Further, since the container body 31 is formed so that the inner side of the bulging portion 33 is wider than the opening portion 34, the spacer 40 is fixed to the container body 31 only by housing the spacer 40 in the bulging portion 33. be able to. Further, since the circumferential surface 43 of the spacer 40 and the opening edge 34A of the opening 34 are formed over the entire circumference, the circumferential surface 43 and the opening edge 34A can be engaged over the entire circumference. . Therefore, the holding force of the spacer 40 with respect to the container body 31 can be further improved.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) In the above-described embodiment, a nonaqueous electrolyte secondary battery is shown as an example of a power storage element. However, the present invention is not limited to this, and the power storage element is a capacitor with an electrochemical phenomenon such as a lithium ion capacitor. Also good.

  (2) In the above embodiment, the power generation element 10 of the battery body B1 is formed in a flat shape by winding the positive electrode plate and the negative electrode plate that are overlapped with the separator interposed therebetween. For example, the power generation element may be formed in another shape such as a cylindrical shape by winding a positive electrode plate and a negative electrode plate, which are overlapped with a separator interposed therebetween. A laminated type in which the plate and the negative electrode plate are laminated without being wound may be used.

  (3) In the above embodiment, the example in which the present invention is applied to the single battery B including one power generation element 10 has been described. However, the present invention is not limited thereto, and the present invention is not limited to a single battery including two or more power generation elements. It can also be applied to batteries.

  (4) In the above embodiment, a part of the container body 31 is bulged to form the bulging portion 33. However, according to the present invention, as shown in FIG. Instead, the recess 37 may be provided on the inner surface side of the thick container body 31, and the spacer 40 may be accommodated in the recess 37.

  (5) In the above embodiment, although the spacer 40 is held inside the bulging portion 33 by engaging the peripheral surface 43 of the spacer 40 and the opening edge portion 34A of the opening portion 34, according to the present invention. Alternatively, the spacer may be held inside the bulging portion by pressing into the bulging portion while elastically deforming the spacer. In this case, the bulging portion may be recessed inward while maintaining the diameter of the opening.

  (6) In the above embodiment, although the opening edge 34A of the opening 34 and the peripheral surface 43 of the spacer 40 are formed over the entire circumference, according to the present invention, the opening edge of the opening or the spacer Any one of the peripheral surfaces may be provided intermittently along the circumferential direction.

DESCRIPTION OF SYMBOLS 10 ... Power generation element 30 ... Exterior body 33 ... Swelling part (concave part)
34 ... Opening 34A ... Opening edge 40 ... Spacer (elastic body)
43 ... peripheral surface (engagement part)
AB ... assembled battery B ... single battery (storage element)

Claims (8)

A power generation element;
An exterior body that houses the power generation element;
An elastic body housed between the power generation element and the exterior body,
The electricity storage element in which the said exterior body is formed with the recessed part which accommodates and hold | maintains the said elastic body inside.   The exterior body is formed by forming a resin sheet into a bag shape, and the recess is formed by bulging a part of the exterior body away from the power generation element. The electricity storage device described.   3. The power storage device according to claim 1, wherein the recess has a shape in which the inner side is wider than the opening, and the elastic body is accommodated in the recess.   The elastic body has an engaging portion that engages with an opening edge portion of the opening portion from the inside, and the engaging portion is formed to extend in a circumferential direction of the elastic body. Item 4. The electricity storage device according to Item 3.   The engaging portion is formed over the entire circumference of the elastic body, while the opening edge portion of the opening is formed to protrude toward the center of the opening over the entire circumference. The electricity storage device according to claim 4. It has electrode terminals for inputting and outputting power,
The electricity storage device according to any one of claims 1 to 5, wherein the elastic body faces a surface adjacent to a surface on which the electrode terminal is disposed, of the outer surface of the power generation element.   A unit cell, which is the electricity storage element according to claim 1.   A battery pack comprising a plurality of the single cells according to claim 7 arranged side by side.

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