JP2010287530A - Battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery pack for reducing variation of battery performance among respective single batteries constituting the battery pack. <P>SOLUTION: In the battery pack 15, broad surfaces 80 of square cases 75 of a plurality of single batteries 20 are respectively arranged so as to face each other, and are restrained in an alignment direction against respective electrode bodies 30A, 30B, 30C, and 30D of respective single batteries in a load-applied state. Further, spacing sheets 100 with the same shapes restrained in a load-applied state in the alignment direction together with respective electrode bodies are respectively arranged on respective broad surfaces of the square cases of the plurality of aligned single batteries. Here, each spacing sheet is formed at a scale arranged in the opposite surface wherein an area of a surface opposite to the broad surface of the square case is minimal among the electrode bodies of the respective single batteries in being restrained, and arranged positions of the whole spacing sheets are arranged in a line along the restraining direction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an assembled battery in which a plurality of chargeable / dischargeable single cells (secondary batteries) are arranged in a predetermined direction (typically, an assembled battery in which the plurality of single cells are connected in series). Specifically, the present invention relates to an assembled battery suitable for mounting on a vehicle.

  Lithium secondary battery (for example, lithium ion battery) that is lightweight and obtains high energy density, nickel-metal hydride battery, other secondary battery, or a storage battery such as a capacitor is a unit cell, and a battery pack in which a plurality of unit cells are connected in series As a power source capable of obtaining a high output, importance is increasing as a power source for mounting on a vehicle or a power source for a personal computer or a portable terminal. In particular, an assembled battery in which a plurality of lithium ion batteries are connected in series as a single battery is expected to be preferably used as a high-output power source for mounting on a vehicle. For example, Patent Document 1 discloses, as an example of an on-board assembled battery, an assembled battery configured by arranging a plurality of identically shaped unit cells made of lithium ion batteries and connecting the unit cells in series. Has been.

JP 2004-227788 A

By the way, as schematically shown in FIG. 7, depending on the manufacturing process, the shape of the electrode body 3 (for example, the height of the electrode body or the like) accommodated in the case 4 of each unit cell 2 used for the construction of the assembled battery 1. “Thickness in the arrangement direction” may vary. In this way, a large number of the unit cells 2 having the electrode bodies 3 having variations in height and thickness are arranged in a predetermined direction, and are restrained between the unit cells 2 via an interval holding plate (for example, a cooling plate) (that is, each unit cell). 2 is fixed to each other), when a set of assembled batteries 1 is manufactured, even if the load applied to each unit cell 2 is the same, due to variations in the height and thickness of the electrode bodies 3, each electrode body Since 3 is different in the arrangement direction and the area of the surface facing (typically in contact with) the case 4 body (inner wall surface) of the unit cells 2 is different, the load (surface pressure) applied to each electrode body 3 may be different. For this reason, the battery performance varies among the single cells 2, and the battery performance as the assembled battery 1 may be deteriorated.
Therefore, the present invention was created to solve the conventional problems related to an assembled battery composed of a plurality of unit cells each having an electrode body having a difference in shape as described above. It is an object of the present invention to provide an assembled battery in which variations in battery performance among the individual cells constituting the battery are reduced.

According to the present invention, a plurality of chargeable / dischargeable rectangular unit batteries (for example, secondary batteries such as lithium ion batteries) are arranged in a predetermined direction (typically, each unit cell is connected in series. ) A configured assembled battery is provided.
In the assembled battery disclosed herein, the unit cell includes an electrode body including a positive electrode and a negative electrode, a rectangular case having two wide surfaces facing each other, which is an exterior case that houses the electrode body and an electrolyte, The positive and negative terminals are respectively positive and negative terminals electrically connected to the positive electrode and the negative electrode, and are square cells having the same shape and having a positive electrode terminal and a negative electrode terminal arranged outside the case. The plurality of unit cells are arranged so that the wide surfaces of the rectangular cases are opposed to each other, and are restrained in a state in which a load is applied to the electrode body of each unit cell in the arrangement direction. Yes.
And on each wide surface of the square case of each of the plurality of unit cells arranged, a spacing sheet having the same shape that is constrained in a state where a load is applied in the arrangement direction is arranged together with each electrode body. ing. Here, when each of the spacing sheets is constrained, the area of the surface (typically, the surface in contact) of the electrode body of each unit cell that faces the wide surface of the case is minimized. It is formed in the scale arrange | positioned in this opposing surface, and the arrangement position of all the space | interval holding | maintenance sheets is arrange | positioned in a line along the restraint direction.

  In this specification, the “single cell” is a term indicating individual power storage elements constituting an assembled battery, and includes batteries and capacitors of various compositions unless otherwise specified. The “secondary battery” refers to a battery that can be repeatedly charged, and includes so-called storage batteries such as lithium ion batteries and nickel metal hydride batteries. The electric storage element constituting the lithium ion battery is a typical example included in the “unit cell” referred to herein, and the lithium ion battery module including a plurality of such unit cells is disclosed in the “assembled battery” Is a typical example.

In the assembled battery having the above-described configuration, each spacing sheet is a scale that is arranged in the facing surface of the electrode body of each unit cell that has the smallest area facing (in contact with) the wide surface of the exterior case. And the arrangement positions of all the spacing sheets are aligned in a line along the constraint direction.
Thus, by forming all the spacing sheets in the same shape and aligning the arrangement positions of all the spacing sheets in a line along the restraint direction, a plurality of single cells can be connected to the wide surface of the square case. Are arranged so as to face each other, and a spacing sheet is arranged on each wide surface of each unit cell, and a set battery is manufactured by restraining by applying a restraining load in the arranging direction, each spacing sheet is The area (pressure receiving area) for pressing each electrode body is the same, and the load (surface pressure) applied to each electrode body is the same.
Therefore, according to the present invention, even when the electrode body of each unit cell has a different surface area facing the wide surface of the outer case due to variations in the height of the electrode body and the thickness in the arrangement direction, it is added to each electrode body. The load (surface pressure) is the same. As a result, it is possible to provide an assembled battery that exhibits stable battery performance (for example, cycle characteristics) by reducing variations in battery performance between the individual cells. From this, the assembled battery disclosed here can be suitably used as a vehicle-mounted secondary battery mounted on an electric vehicle or a hybrid vehicle as a power source.

In a preferred aspect of the assembled battery disclosed herein, the plurality of single cells prevent gas flow between the square case and the outside, and the internal pressure in the case has increased beyond a predetermined level. Each has a safety valve that opens. In each of the plurality of single cells, the lower end of the electrode body is disposed at a position separated from the lower surface of the square case by a predetermined same distance.
In the assembled battery having such a configuration, even when the battery reaction proceeds rapidly during overcharge or the like and gas is generated inside the sealed battery case, the path for the gas to reach the safety valve Is secured.

  In another preferable aspect of the assembled battery disclosed herein, the spacing sheet is formed of an insulating member. By using an insulating sheet (typically a sheet made of an insulating synthetic resin) as a spacing sheet disposed between the single cells, an assembled battery with higher electrical reliability can be configured.

In another preferred embodiment of the assembled battery disclosed herein, the electrode body is a flat wound electrode body in which a positive electrode sheet and a negative electrode sheet are wound through a separator sheet, Each flat surface of the electrode body is disposed in the square case so as to face each wide surface of the square case.
The height and thickness dimensions of the flat wound electrode body tend to be uneven depending on the degree and state of the winding. Therefore, in the unit cell including such a wound electrode body, the surface area facing (contacting) the wide inner wall of the square case is likely to vary. By using, the area (pressure receiving area) where the spacing sheet presses each wound electrode body when restrained is the same, and the load (surface pressure) applied to each electrode body is also the same. For this reason, according to the assembled battery of this aspect, there is provided an assembled battery that includes a plurality of single cells having a flat wound electrode body as a constituent element and that can reduce variation in battery performance among the single cells. be able to.

It is a perspective view which shows typically the structure of the assembled battery which concerns on one embodiment of this invention. It is a side view which shows typically the structure of the assembled battery which concerns on one embodiment of this invention. It is a front view which shows typically an example of a wound electrode body. FIG. 2 is a cross-sectional view schematically showing each electrode body, which is an assembled battery according to an embodiment of the present invention, and which has a variation in height dimension accommodated in a container of each unit cell in a restrained state shown in FIG. It is. FIG. 3 is a cross-sectional view schematically showing each electrode body that is a battery pack according to another embodiment and that has a variation in thickness dimension that is accommodated in a container of each unit cell in a constrained state shown in FIG. 2. is there. It is a side view which shows typically the vehicle (automobile) provided with the assembled battery which concerns on this invention. It is sectional drawing which shows typically the state which restrained the several cell through the space | interval holding sheet of the conventional shape.

  Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings. In addition, matters other than matters specifically mentioned in the present specification (for example, the structure of the unit cell as a component of the assembled battery, the shape and the arrangement position of the spacing sheet), and matters necessary for the implementation of the present invention ( For example, the configuration and manufacturing method of the positive electrode, the negative electrode, and the separator, the manufacturing method of the electrode body, the restraint method of the unit cell, and the assembled battery mounting method on the vehicle) can be grasped as design matters for those skilled in the art based on the conventional technology in the field. . The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field.

The assembled battery according to the present invention may be an assembled battery in which a chargeable / dischargeable secondary battery is a single battery and a plurality of such single batteries are connected in series, and the structure of the single battery is not particularly limited. For example, a secondary battery such as a nickel-hydrogen battery, a nickel-cadmium battery, a lead storage battery, a nickel-zinc battery, or a secondary battery of an electric double layer capacitor (that is, a physical battery) is a battery suitable for carrying out the present invention. As a configuration. A battery configuration particularly suitable for the implementation of the present invention is a lithium secondary battery (typically a lithium ion battery). Since the lithium secondary battery is a battery that can achieve a high output with a high energy density, it is possible to construct a high-performance assembled battery, particularly an assembled battery (battery module) for mounting on a vehicle.
Although not intended to be particularly limited, the present invention will be described in detail below by taking a lithium ion battery as an example of the battery configuration.

  Hereinafter, the configuration of the assembled battery of the present invention will be described with reference to the drawings. In the following drawings, members / parts having the same action are described with the same reference numerals. FIG. 1 is a perspective view showing the configuration of the assembled battery according to the first embodiment. FIG. 2 is a side view showing the configuration of the assembled battery according to the first embodiment.

As shown in FIG. 1, the assembled battery 15 according to the present embodiment (first embodiment) includes a plurality (four in the present embodiment as shown) of chargeable / dischargeable cells 20 arranged in a predetermined direction. (In the present embodiment, each unit cell is connected in series as shown in the figure). The unit cell 20 constituting the assembled battery 15 according to the present embodiment is typically a predetermined battery constituent material (active material for each positive and negative electrode, collection of each positive and negative electrode), similarly to the unit cell constituting the conventional assembled battery. An electrode body 30 including an electric body, a separator, and the like, and a square case 75 that accommodates the electrode body 30 and an appropriate liquid electrolyte (electrolytic solution).
The rectangular case 75 only needs to have a shape that can accommodate a flat wound electrode body 30 (hereinafter also simply referred to as “wound electrode body 30”), which will be described later. A rectangular parallelepiped shape (typically a flat shape) having surfaces 80 and 80 (a surface having the largest area and facing a flat surface of a flat-shaped wound electrode body 30 described later housed in the case 75). Box-shaped case). The material of the square case 75 is not particularly limited as long as it is the same as that used in the conventional single battery. From the viewpoint of reducing the weight of the assembled battery itself, for example, a thin metal or synthetic resin container may be used.

On the upper surface of the square case 75, a positive electrode terminal 85 electrically connected to the positive electrode of the wound electrode body 30 and a negative electrode terminal 90 electrically connected to the negative electrode are provided. As shown in FIG. 1, one positive electrode terminal 85 and the other negative electrode terminal 90 are electrically connected by a connector 95 between adjacent unit cells 20. Thus, the assembled battery 15 which has a desired voltage is constructed | assembled by connecting each cell 20 in series.
Similar to the conventional case, a safety valve (not shown) for discharging the gas generated inside the case 75 to the outside of the case 75 is provided on the upper surface side of the square case 75. The safety valve can be used without any limitation as long as it has a mechanism that opens and discharges gas to the outside of the case 75 when the pressure inside the case 75 rises above a predetermined level.

  As shown in FIG. 1 and FIG. 2, the plurality of single cells 20 having the same shape are square-shaped while being inverted one by one so that the positive terminals 85 and the negative terminals 90 are alternately arranged at regular intervals. The wide surfaces 80 of the cases 75 are arranged in the facing direction. Furthermore, on each wide surface of each of the plurality of unit cells 20 (that is, between each unit cell and on both outer sides of the plurality of unit cells arranged) 80, a spacing sheet 100 having a predetermined shape, which will be described later, is provided. It arrange | positions in the state closely_contact | adhered to the wide surface 80 of a case (Hereinafter, the several unit cell 20 and the some space | interval holding | maintenance sheet | seat 100 which were arranged are generically called the "single cell group 25".). The spacing sheet 100 is preferably made of a material and / or shape that can function as a heat radiating member for radiating heat generated in each unit cell 20 during use. For example, a spacing sheet made of metal with good thermal conductivity or lightweight, hard polypropylene or other synthetic resin is suitable. More preferably, the spacing sheet 100 is made of an insulating member. For example, an insulating spacing sheet made of synthetic resin such as olefin resin such as polypropylene is preferable. Alternatively, it may be a metal spacing sheet whose surface is insulated. The arrangement position of each spacing sheet 100 will be described in detail later.

  As shown in FIGS. 1 and 2, a pair of end plates 105, 105 are closely arranged on the outer side in the arrangement direction of the spacing sheets 100, 100 arranged on both outer sides in the unit cell group 25. Yes. Further, the fastening beam members 110 are attached to both side surfaces of the unit cell group 25 along the arrangement direction so as to bridge the pair of end plates 105, 105. Then, as shown in FIG. 2, each end of the beam member 110 is fastened and fixed to the end plate 105 with screws 115, so that a predetermined load is applied to each unit cell 20 and each spacing sheet 100 in the arrangement direction. It can be constrained to join.

Next, the configuration of the unit cell 20 suitable for configuring the assembled battery according to the present embodiment will be described with reference to the drawings. FIG. 3 is a front view of the wound electrode body 30 accommodated in the square case 75 as viewed from the wide flat plane side.
As shown in FIG. 3, the wound electrode body 30 according to the present embodiment measures a sheet-like positive electrode (positive electrode sheet) 35 and a sheet-like negative electrode (negative electrode sheet) 50 in the same manner as an electrode body of a normal lithium ion battery. Laminated together with two sheet-like separators (separator sheets) 65, and the positive electrode sheet 35 and the negative electrode sheet 50 are wound while being slightly shifted in the width direction (winding axis direction), and the obtained wound body is then side-faced. It is a flat-shaped wound electrode body 30 produced by crushing from the direction and causing it to be ablated.

  As shown in FIG. 3, as a result of winding the wound electrode body 30 with a slight shift in the width direction, part of the ends of the positive electrode sheet 35 and the negative electrode sheet 50 are respectively wound core portions 70 (that is, the positive electrode sheet 35). The positive electrode active material layer forming portion, the negative electrode active material layer forming portion of the negative electrode sheet 50, and the separator sheet 65 are closely wound around). A positive electrode lead terminal 45 and a negative electrode lead terminal 60 are attached to the protruding portion 40 (that is, the portion where the positive electrode active material layer is not formed) and the protruding portion 55 (that is, where the negative electrode active material layer is not formed), respectively. Are electrically connected to the positive terminal 85 and the negative terminal 90, respectively.

The material and the member constituting the wound electrode body 30 may be the same as those of a conventional lithium ion battery, and are not particularly limited. For example, the positive electrode sheet 35 can be formed by applying a positive electrode active material layer for a lithium ion battery on a long positive electrode current collector. For the positive electrode current collector, an aluminum foil (this embodiment) or other metal foil suitable for the positive electrode is preferably used. As the positive electrode active material, one or more of materials conventionally used in lithium ion batteries can be used without any particular limitation. Preferable examples include lithium ion transition metal oxides such as LiMn ₂ O ₄ , LiCoO ₂ , and LiNiO ₂ . On the other hand, the negative electrode sheet 50 may be formed by applying a negative electrode active material layer for a lithium ion battery on a long negative electrode current collector. For the negative electrode current collector, a copper foil (this embodiment) or other metal foil suitable for the negative electrode is preferably used. As the negative electrode active material, one or more of materials conventionally used in lithium ion batteries can be used without any particular limitation. Preferable examples include carbon-based materials such as graphite carbon and amorphous carbon, lithium-containing transition metal oxides and transition metal nitrides.

  Moreover, as a suitable sheet-like separator 65 used between the positive electrode sheet 35 and the negative electrode sheet 50, what was comprised with the porous polyolefin-type resin is mentioned. When a fixed electrolyte or a gel electrolyte is used as the electrolyte, a general resin separator sheet may not be necessary (that is, in this case, the electrolyte itself may function as a separator).

As the electrolyte accommodated in the rectangular case 75 together with the wound electrode body 30, the same electrolyte as the non-aqueous electrolyte conventionally used in lithium ion batteries can be used without any particular limitation. For example, a lithium salt such as LiPF ₆ can be used. An appropriate amount (for example, concentration 1M) of lithium salt such as LiPF ₆ is dissolved in a non-aqueous electrolyte such as a mixed solvent of diethyl carbonate and ethylene carbonate (for example, a mass ratio of 1: 1) and used as an electrolyte. it can.

  Then, as shown in FIG. 4, the obtained flat wound electrode body 30 is placed in the square case 75 of each unit cell 20, and each flat surface of the electrode body 30 is formed on each wide surface 80 of the square case 75. It accommodates each so that it may oppose. At this time, it is preferable to align the position of the lower end of each wound electrode body 30 with a jig. Specifically, it is preferable that the distance from the lower surface of the inner wall of each square case 75 to the lower end edge of the wound electrode body 30 is set to a certain distance (for example, about 1 mm). Thereby, a space (a space between the safety valve and the upper end edge of the wound electrode body 30) in which gas can stay can be widely provided on the upper surface side in the square case 75. Even if a problem such as overcharging occurs in the unit cell and gas is generated inside the case, a gas flow path to reach the safety valve is secured, so when the abnormal internal pressure rises due to gas, it is ensured A safety valve can be activated.

  The height dimension of the flat wound electrode body 30 (that is, the dimension from the upper end to the lower end in the vertical direction of the wound electrode body 30 when the wound electrode body 30 is accommodated in the square case 75) and the thickness The dimensions (that is, the thickness dimension in the arrangement direction of the wound electrode body 30 when the wound electrode body 30 is accommodated in the square case 75) may be uneven depending on the degree of winding and the state. Therefore, when the wound electrode body 30 is accommodated in the rectangular case 75, the flat surface of the wound electrode body 30 faces the inner wall of the wide surface 80 of the rectangular case 75 (typically in contact with it). The surface area may vary. A plurality of such cells 20 are arranged so that the wide surfaces 80 of the square cases 75 face each other, and the wide surfaces 80 of the respective square cases 75 are held at the same shape as the wide surfaces 80 of the square cases 75. Even when the restraint load applied to each unit cell 20 (square case 75) is the same when the sheet is arranged and restrained in the arrangement direction, the electrode body 30 accommodated in each unit cell 20 Since the area (pressure receiving area) where the electrode body 30 faces the case 75 is different, the load (surface pressure) received by the electrode body 30 is also different, and the battery performance of each electrode body 30 varies, and the battery performance as the assembled battery 15 May decrease.

As shown in FIG. 4, in this embodiment, the interval holding sheets 100 have the same shape, and the interval holding sheets 100 are arranged in a line along the restraining direction (arrangement direction) of the unit cells 20.
More specifically, as shown in the figure, each of the electrode bodies 30A, 30B, 30C, 30D has height dimensions h1, h2, h2, h3 (h1>h2> h3), and is between the electrode bodies 30A-30D. There are variations in the height dimension. At this time, among the wound electrode bodies 30 </ b> A to 30 </ b> D of each unit cell 20, the part where the electrode bodies 30 </ b> A to 30 </ b> D are opposed to (typically in contact with) the inner wall of the wide surface 80 of the square case 75. The surface having the smallest surface area (ie, the surface where the electrode bodies 30A to 30D are opposed to (in contact with) the inner wall of the wide surface 80 of the square case 75 and have the smallest height dimension) .), The spacing sheet 100 is formed in the same shape. As shown in FIG. 4, each spacing sheet 100 is formed so that the electrode body 30 </ b> D can be disposed in the plane of the portion facing the square case 75.
When a restraining load is applied in the arrangement direction, the rectangular case 75 of each unit cell 20 is placed at the same position on the wide surface 80 of the rectangular case 75 of each unit cell 20 so as to press the minimum area portion. A spacing sheet 100 is disposed. That is, the arrangement positions of all the spacing sheets 100 are aligned in a row along the constraint direction with the minimum area portion as a reference.
From the above, by using the spacing sheet 100 disclosed herein, each electrode when the plurality of unit cells 20 are constrained even when the height dimensions of the electrode bodies 30A to 30D vary. The pressure receiving area of the body 30 is the same. Thereby, the restraint load (surface pressure) applied to each electrode body 30 becomes the same, and the assembled battery 15 in which the variation in battery performance among the individual cells 20 at the time of restraint is reduced can be constructed.

In the first embodiment described above, the example in which the height dimension of the wound electrode body accommodated in the square case has a variation is shown. However, the present invention is not limited to such an example. For example, as shown in FIG. The present invention can also be suitably implemented when there are variations in the thickness dimensions of the wound electrode bodies 230A, 230B, 230C, and 230D housed in the mold case 75. Hereinafter, as a second embodiment, a case will be described in which the thickness dimension of each electrode body varies.
As shown in FIG. 5, the electrode body 230 </ b> A has a thickness dimension t <b> 1 slightly larger than the thickness dimension of the rectangular case 75 (that is, the dimension from the inner wall of one wide surface 80 to the inner wall of the other wide surface 80). Therefore, the square case 75 slightly swells when accommodated in the square case 75. On the other hand, since the electrode body 230D has a thickness dimension t3 that is slightly smaller than the thickness dimension of the square case 75, a slight gap is provided between the electrode body 230D and the case 75 when accommodated in the square case 75. Occurs. Thereby, when restrained in the arrangement direction, the rectangular case 75 is bent toward the inside of the case 75. The electrode bodies 230 </ b> B and 230 </ b> C have thickness dimensions t <b> 2 and t <b> 2 that are approximately the same as the thickness dimension of the square case 75, respectively. The thickness dimension is t1>t2> t3. At this time, among the electrode bodies 230 </ b> A to 230 </ b> D of each unit cell 220, the area of the surface of the portion where the electrode bodies 230 </ b> A to 230 </ b> D are opposed to (in contact with) the inner wall of the wide surface 80 of the square case 75 is the largest. It is arranged in a small surface (that is, a surface in which the height dimension of the surface of the portion where the electrode bodies 230A to 230D are opposed to (in contact with) the inner wall of the wide surface 80 of the square case 75 is the minimum). Each spacing sheet 200 is formed in the same shape so as to be able to. As shown in FIG. 5, each spacing sheet 200 is formed so that the electrode body 230 </ b> A can be disposed in the plane of the portion facing the square case 75, and the first embodiment described above. Similarly to the case, the interval holding sheet 200 is arranged. Thereby, even if it is a case where dispersion | variation has arisen in the thickness dimension of each electrode body 230A-230D, the assembled battery 215 which has an effect similar to 1st Embodiment mentioned above can be constructed | assembled. In particular, when there is a gap between the electrode body and the inner wall of the wide surface of the square case, the conventional gap maintaining sheet presses the entire wide surface of the square case to restrain the load on the electrode body. However, according to the present embodiment, each of the electrodes is caused by the spacing sheet 200 pressing the square case 75 (slightly bending the square case 75). Since the pressure receiving areas of the bodies 230A to 230D are the same, it can be preferably applied.
In addition, even if it is a case where dispersion | variation has arisen about both the height dimension and thickness dimension of each electrode body, there exists an effect similar to the said embodiment by arrange | positioning a space | interval holding sheet similarly to the said embodiment. An assembled battery can be constructed.

  In addition, since the assembled batteries 15 and 215 according to the above embodiment can output a large current, they can be suitably used as a power source for a motor (electric motor) mounted on the vehicle 10 such as an automobile. That is, as shown in FIG. 6, a vehicle 10 including the assembled batteries 15 and 215 according to the above embodiment as a power source (typically, an automobile including an electric motor such as an automobile, particularly a hybrid automobile, an electric automobile, and a fuel cell automobile). Can be provided.

As mentioned above, although this invention was demonstrated by suitable embodiment, such description is not a limitation matter and of course various modifications are possible. For example, when the electrode body is accommodated in the square case, a sheet may be inserted so as to close a gap that may be generated between the electrode body and the square case.
The configuration of the electrode body is not limited to the wound type as described above, and may be, for example, a laminated type electrode body (laminated electrode body) formed by alternately laminating positive and negative electrode sheets together with a separator sheet.
In addition, when mounted on a vehicle such as an automobile, more unit cells can be connected in series, and an exterior cover for protecting the main part (unit cell group, etc.) of the assembled battery and a predetermined part of the vehicle. A part for fixing the battery, a part for connecting a plurality of assembled batteries (battery modules) to each other can be provided, but the presence or absence of such an equipment does not affect the technical scope of the present invention. .

DESCRIPTION OF SYMBOLS 1 assembled battery 2 single battery 3 electrode body 4 case 5 spacing holding plate 10 vehicle 15 assembled battery 20 single battery 25 single battery group 30, 30A, 30B, 30C, 30D flat-shaped wound electrode body 35 sheet-like positive electrode (positive electrode sheet) )
40 Positive electrode protruding portion 45 Positive electrode lead terminal 50 Sheet-like negative electrode (negative electrode sheet)
55 Negative electrode protruding part 60 Negative electrode lead terminal 65 Separator sheet (separator)
70 Winding core portion 75 Square case 80 Wide surface 85 Positive electrode terminal 90 Negative electrode terminal 95 Connector 100 Spacing sheet 105 End plate 110 Beam material (constituted from one)
115 Screw 200 Spacing retention sheet 215 Battery pack 220 Single cell 230A, 230B, 230C, 230D Flat-shaped wound electrode body

Claims (5)

A battery pack comprising a plurality of chargeable / dischargeable rectangular parallelepiped prismatic cells arranged in a predetermined direction,
The unit cell includes an electrode body including a positive electrode and a negative electrode, an outer case containing the electrode body and an electrolyte, and a rectangular case having two wide surfaces facing each other, and the positive electrode and the negative electrode are electrically connected to each other. The positive and negative terminals are square unit cells having the same shape and provided with a positive electrode terminal and a negative electrode terminal arranged on the outside of the case,
The plurality of unit cells are arranged so that the wide surfaces of the rectangular cases face each other, and are constrained in a state where a load is applied to the electrode bodies of the unit cells in the arrangement direction,
On each wide surface of each of the square cases of each of the plurality of arranged cells, a spacing sheet having the same shape that is constrained in a state where a load is applied in the arrangement direction is arranged together with each electrode body. And
Here, when each of the spacing sheets is constrained, the scale is arranged in the facing surface of the electrode body of each unit cell having the smallest surface area facing the wide surface of the case. The assembled battery is characterized in that all of the spacing sheets are arranged in a line along the constraint direction. The plurality of single cells each include a safety valve that prevents gas from flowing in and out of the square case and opens when the internal pressure in the case rises above a predetermined level.
2. The assembled battery according to claim 1, wherein in each of the plurality of unit cells, the lower end of the electrode body is disposed at a position separated from the lower surface of the square case by a predetermined same distance.   The assembled battery according to claim 1, wherein the spacing sheet is made of an insulating member.   The electrode body is a flat wound electrode body in which a positive electrode sheet and a negative electrode sheet are wound through a separator sheet, and each flat surface of the electrode body is opposed to each wide surface of the square case. The assembled battery according to any one of claims 1 to 3, wherein the assembled battery is disposed in the square case.   A vehicle provided with the assembled battery according to claim 1.

Images