JP6141732B2 - Battery stack and battery pack - Google Patents

Description

  The present invention relates to a battery laminate in which a plurality of thin plate-like battery cells are stacked. Moreover, this invention relates to the battery pack which accommodated the said battery laminated body in the housing | casing.

  Non-aqueous electrolyte secondary batteries typified by lithium ion secondary batteries are characterized by high energy density, so various mobile devices such as automobiles and motorcycles, personal digital assistants, uninterruptible power supplies (UPS (Uninterruptible Power Supply)) It is used as a power source for power storage devices and the like. Furthermore, in order to obtain a desired battery capacity, a battery pack in which a battery stack in which a plurality of secondary batteries (battery cells) connected in series are stacked is housed in a casing is also in practical use.

  As a battery cell used for a battery pack, a laminated battery cell in which a thin plate-shaped power generation element is packaged with a flexible laminate sheet is often used. Since the laminated battery cell has a substantially rectangular outer shape, the mounting efficiency is higher than that of a cylindrical battery cell in which a cylindrical power generation element is housed in a cylindrical metal container. Moreover, since the exterior is a sheet, it is lightweight. Therefore, when compared with the same volume, the battery pack using the laminated battery cell has a large battery capacity and is lighter than the battery pack using the cylindrical battery cell.

  As a battery pack using a thin laminated battery cell, a structure in which a battery stack in which a plurality of battery cells are integrated using an adhesive tape is housed in a housing is known (see, for example, Patent Document 1). ).

JP 2012-89470 A (FIG. 10)

  Conventional battery stacks for battery packs are generally manufactured by alternately stacking battery cells and insulating plates for ensuring insulation between the battery cells. The battery cell and the insulating plate are fixed using a double-sided adhesive tape. Since the laminated battery cell is obtained by sheathing the power generation element with a flexible sheet, it is easily deformed and has poor dimensional accuracy. Therefore, it takes much time to manufacture a battery stack by stacking such a plurality of battery cells with high positional accuracy.

  On the other hand, if each battery cell is stored in a hard case, the handleability of the battery cell is improved. It is relatively easy to produce a battery stack by sequentially stacking cases containing battery cells. However, since the battery stack increases in size, the mounting efficiency of the battery cells decreases.

  An object of this invention is to provide the battery laminated body and battery pack which are easy to manufacture, without impairing the characteristic of the laminated battery cell which is excellent in mounting efficiency.

  The battery laminate of the present invention includes a plurality of thin plate-like battery cells and a plurality of cases each housing the plurality of battery cells. Each of the plurality of battery cells includes a flexible sheet that covers the power generation element. A sealed region where the sheet is sealed is formed along the outer periphery of the battery cell. On one surface of the battery cell, a convex portion due to the power generation element protrudes with respect to the seal region. Each of the plurality of cases includes a frame in which a seal region storage portion for storing the seal region of the battery cell is formed on a surface thereof, and a main storage that is surrounded by the frame and stores the convex portion of the battery cell. A part. The bottom surface of the main storage portion is composed of a plurality of strip plates that are arranged in parallel and spaced apart from each other. There is an opening between adjacent strip plates. The plurality of cases are stacked with their front and back being alternately inverted. The plurality of strip plates of one case of two cases adjacent to each other with the back surfaces opposite to the front surface on which the seal region storage portion is formed are It is inserted in a plurality of openings between the plurality of strip plates.

  The battery pack of the present invention includes the above-described battery stack of the present invention and a housing that houses the battery stack.

  According to the present invention, since battery cells can be handled in a state of being housed in a case in the production of a battery laminate, the handleability of the battery cells is improved. Thereby, manufacture of a battery laminated body becomes easy.

  The bottom surface of the main storage part of the case is composed of a plurality of strip plates. A plurality of strip plates of one case out of two cases whose back surfaces are opposed to each other are fitted into a plurality of openings of the other case. Thereby, the fall of the mounting efficiency by having accommodated the battery cell in the case can be suppressed. In addition, since insulation between the two battery cells stored in the two cases is ensured, there is no need to interpose an insulating sheet between the two battery cells. Thereby, manufacture of a battery laminated body becomes easy.

  Therefore, according to the present invention, it is possible to realize a battery stack and a battery pack that are easy to manufacture while suppressing a decrease in the mounting efficiency of the battery cells.

FIG. 1A is a perspective view seen from one side of a battery cell constituting a battery stack according to an embodiment of the present invention, and FIG. 1B is a perspective view seen from the other side. FIG. 2 is an exploded perspective view conceptually showing a state in which a plurality of battery cells are stacked in series in the battery stack according to the embodiment of the present invention. FIG. 3 is a perspective view of a case constituting the battery stack according to the embodiment of the present invention. FIG. 4A is a top view of a case constituting the battery stack according to the embodiment of the present invention. FIG. 4B is a bottom view of the case constituting the battery stack according to the embodiment of the present invention. FIG. 4C is a side view of the case as viewed along arrow 4C in FIG. 4D is a cross-sectional view of the case along the plane including the line 4D-4D in FIG. 3. FIG. 5 is an exploded perspective view illustrating a state in which the battery cell is housed in the case according to the embodiment of the present invention. FIG. 6 is an exploded perspective view of a unit formed by stacking two cases each containing a battery cell in an embodiment of the present invention. 7 is an enlarged cross-sectional view of the through hole along the plane including line 7-7 in FIG. 4A. FIG. 8 is a perspective view of a unit laminate in which the two units shown in FIG. 6 are laminated in an embodiment of the present invention. FIG. 9 is a cross-sectional view of the unit laminate along the plane including line 9-9 in FIG. FIG. 10 is an exploded perspective view showing a temperature detection element inserted into a notch formed in an insulating sheet in one embodiment of the present invention. FIG. 11A is a perspective view of the unit laminate with the heat sink attached in FIG. 11B is a cross-sectional view of the unit laminate body taken along the plane including the line 11B-11B in FIG. 11A. FIG. 11C is an enlarged cross-sectional view of the portion 11C of FIG. 11B. FIG. 12 is an enlarged perspective view showing a method of connecting electrode tabs in the unit laminate body shown in FIG. FIG. 13 is a perspective view of a battery stack according to an embodiment of the present invention. FIG. 14 is a perspective view of a battery stack according to an embodiment of the present invention to which a circuit board is attached. FIG. 15 is a cross-sectional view of a battery pack according to an embodiment of the present invention.

  In the battery laminate of the present invention described above, it is preferable that all of the plurality of battery cases have the same shape. This is advantageous for facilitating the production and efficiency of the battery stack. In addition, since it is possible to mass-produce a single type of case, the cost of the battery stack can be reduced.

  A through hole may be formed in each frame of the plurality of cases. In this case, it is preferable that the through holes form continuous holes that are continuous in the stacking direction of the plurality of cases. And it is preferable that the connection member inserted in the said continuous hole has connected the said some case. Thereby, since a plurality of cases can be connected and integrated by inserting a connecting member into the continuous hole, the battery laminate can be manufactured as compared with the conventional method using a double-sided adhesive tape. It becomes easy. Also, if it becomes necessary to disassemble the battery stack, each battery cell can be easily taken out without being damaged.

  The edge of the opening on the surface side of the through hole may protrude or sink compared to the peripheral region. In this case, the protrusion formed on the edge of the opening of one case of the two cases facing each other and facing each other is a depression formed on the edge of the opening of the other case. It is preferable to fit in. Thereby, the possibility that the battery cell sheet contacts the connecting member inserted into the through hole to cause a short circuit can be reduced.

  An insulating sheet may be provided between the two adjacent battery cells with the surfaces opposite to the convex portions facing each other. Thereby, the insulation between the said two battery cells can be ensured more reliably.

  The battery laminate of the present invention may further include a temperature detection element for detecting the temperature of the battery cell. In this case, it is preferable that the temperature detection element is inserted into a notch formed in the insulating sheet. Thereby, a temperature detection element can be provided in a required location, ensuring the insulation between adjacent battery cells and suppressing an increase in the thickness of the battery stack.

  Each of the plurality of battery cells may include a pair of electrode tabs. In this case, one electrode tab of the pair of electrode tabs of one of the two battery cells adjacent to each other with the insulating sheet interposed therebetween is an electrode facing the one electrode tab of the other battery cell. It may be electrically connected to the tab. The other electrode tab of the one battery cell and the electrode tab facing the other electrode tab of the other battery cell are bent so as to be separated from each other at the first bent portion outside the case. The second bent portion that is farther from the case than the first bent portion may be bent in the opposite direction to the first bent portion. The portion of the insulating sheet that protrudes from the case between the other electrode tab and the electrode tab that faces the other electrode tab is farther than the first bent portion and the other electrode tab. It is preferable to extend to a position closer to the tip and the tip of the electrode tab facing the other electrode tab. Thereby, the protrusion length from the case of the part (insulation tab) of the insulating sheet which protruded from the case can be made small, ensuring the insulation between these two electrode tabs. This makes it possible to reduce the area of the insulating sheet, which is advantageous for cost reduction.

  A heat sink may be provided between the adjacent cases. Thereby, the temperature rise of a battery cell can be suppressed.

  The heat radiating plate may be provided between the two cases whose back surfaces are opposed to each other and adjacent to each other. In this case, it is preferable that the heat radiating plate is deformed in a zigzag shape and disposed between the plurality of strip plates of the two cases. Thereby, it can suppress that the distance between two cases increases by providing a heat sink. This is advantageous for suppressing a decrease in the mounting efficiency of the battery cells.

  The battery laminate of the present invention may further include a circuit board. In this case, it is preferable that the circuit board is fixed to the frame of the case. Thereby, even if vibration or impact is applied, the possibility that the battery stack (particularly the case) collides with the circuit board and the circuit board is broken or damaged is reduced.

  It is preferable that a screw hole for fastening a bolt for fixing the circuit board is formed on the outer surface of the frame. Thereby, a circuit board can be firmly fixed using the said screw hole.

  It is preferable that the electrode tab led out from the battery cell is soldered to the circuit board. Thereby, in the manufacture of the battery stack, the process of electrically connecting the electrode tab and the circuit board can be greatly simplified.

  Below, this invention is demonstrated in detail, showing suitable embodiment. However, it goes without saying that the present invention is not limited to the following embodiments. For convenience of explanation, the drawings referred to in the following description show only the main members necessary for explaining the present invention in a simplified manner among the constituent members of the embodiment of the present invention. Therefore, the present invention can include any member not shown in the following drawings. Further, in the following drawings, the actual dimensions of the members and the dimensional ratios of the members are not faithfully represented.

<Battery cell>
The battery cell 10 which comprises the battery laminated body concerning one Embodiment of this invention is demonstrated.

  FIG. 1A is a perspective view seen from one side of the battery cell 10, and FIG. 1B is a perspective view seen from the other side. The battery cell 10 has a substantially rectangular shape in plan view, and has a thin plate shape that is thinner than the vertical and horizontal dimensions of the substantially rectangular shape. In the battery cell 10, a thin plate-shaped power generation element (not shown) having a substantially rectangular plan view shape is enclosed in an exterior made of a laminate sheet 13 together with an electrolytic solution. The power generation element includes a positive electrode in which a positive electrode mixture layer including a positive electrode active material is applied and formed on both surfaces of a predetermined region of the positive electrode current collector, and a negative electrode mixture layer including a negative electrode active material on both surfaces of the predetermined region of the negative electrode current collector Is an electrode laminate in which negative electrodes formed by coating are alternately laminated via separators. The type of the battery is not particularly limited, but a secondary battery, particularly a lithium ion secondary battery is preferable.

  The laminate sheet 13 is thinner than the power generation element and has flexibility. The laminate sheet 13 may be a flexible multilayer sheet in which a heat-fusible resin layer (for example, a modified polyolefin layer) is laminated on the surface of the base layer made of aluminum or the like on the side facing the power generation element. Good. One rectangular laminate sheet 13 is folded in two at the lower side (one short side) 12b so as to sandwich the power generation element, and is overlapped along the three sides 12a, 12s, 12s other than the lower side 12b to form a seal region. 16 is sealed by a heat sealing method or the like.

  A positive electrode tab 11p and a negative electrode tab 11n are led out from an upper side (the other short side) 12a facing the lower side 12b. The positive electrode tab 11p and the negative electrode tab 11n have a strip shape and extend along a direction orthogonal to the upper side 12a (that is, a direction parallel to a pair of side sides (long sides) 12s adjacent to the upper side 12a). Yes. The positive electrode tab 11p is made of, for example, an aluminum thin plate, and is electrically connected to a plurality of positive electrode current collectors (not shown) constituting the power generation element. The negative electrode tab 11n is made of, for example, a copper thin plate, a nickel-plated copper thin plate, or a copper / nickel clad material, and is electrically connected to a plurality of negative electrode current collectors (not shown) constituting the power generation element. It is connected to the. In the following description, when it is not necessary to distinguish the polarities of the positive electrode tab 11p and the negative electrode tab 11n, these may be referred to as “electrode tabs”.

  As shown in FIG. 1A, a rectangular region due to the power generation element protrudes from the seal region 16 along the three sides 12a, 12s, and 12s of the battery cell 10, and a convex portion 15 is formed. Yes. In the seal region 16 along the upper side 12a, tab seal portions 17p and 17n that slightly protrude to the same side as the convex portion 15 are formed by sealing the electrode tabs 11p and 11n. In the present invention, the direction in which the protrusion 15 protrudes from the seal region 16 is referred to as the “thickness direction” of the battery cell 10. As shown in FIG. 1B, the surface (back surface) of the battery cell 10 opposite to the surface from which the convex portion 15 and the tab seal portions 17p and 17n protrude is a flat surface having substantially no unevenness.

  In the present invention, the configuration of the battery cell is not limited to the above. For example, a battery cell of a four-side seal type in which a power generation element is sandwiched between two rectangular laminate sheets and two laminate sheets are sealed along four sides may be used. The positive electrode tab 11p and the negative electrode tab 11n may be disposed opposite to those in FIGS. 1A and 1B.

  As shown in FIG. 2, a plurality of battery cells 10 are stacked in the thickness direction to form a battery stack 20. In the battery stack 20 of the present invention, each battery cell 10 is housed in a case 30 (see FIG. 3) as will be described later, but in FIG. 2, battery stacks other than the battery cell 10 are shown in order to simplify the drawing. Illustration of members constituting the body 20 is omitted. The direction in which the battery cells 10 are stacked (lateral direction in FIG. 2) is referred to as “stacking direction”. As shown in FIG. 2, the plurality of battery cells 10 are arranged so that tabs of different polarities (that is, positive electrode tab 11p and negative electrode tab 11n) face each other in the stacking direction between two adjacent battery cells 10. Every other battery cell 10 is turned over. As indicated by a two-dot chain line 21, the positive electrode tab 11p and the negative electrode tab 11n facing each other in the stacking direction are electrically connected. As a result, the plurality of battery cells 10 are connected in series. The positive electrode tab 11 p ′ and the negative electrode tab 11 n ′ at both ends that are not connected to the different polarity tab serve as input / output tabs for inputting / outputting power to / from the battery stack 20. The number of battery cells 10 constituting the battery stack 20 can be arbitrarily set.

<Case>
A case 30 constituting a battery stack according to an embodiment of the present invention will be described.

  FIG. 3 is a perspective view of the case 30. 4A is a top view of the case 30, and FIG. 4B is a bottom view of the case 30. FIG. 4C is a side view of the case 30 as viewed along the arrow 4C in FIG. 4D is a cross-sectional view of the case 30 taken along the plane including the line 4D-4D in FIG. For convenience of the following description, an XYZ orthogonal coordinate system in which an axis parallel to the short side of the case 30 is an X axis, an axis parallel to the long side is a Y axis, and an axis perpendicular to the X axis and the Y axis is a Z axis. Set. In the present invention, the X-axis direction may be referred to as the “width direction” and the Z-axis direction may be referred to as the “thickness direction”.

  As shown in FIG. 3, a main storage portion 35 that is a recess having a substantially rectangular plan view shape is formed on one surface of the case 30. The main storage portion 35 is surrounded by a substantially rectangular frame 31. In the present invention, the surface on which the main storage portion 35 is formed is called the “front surface” of the case 30, and the surface opposite to the front surface is called the “back surface” of the case 30.

  Of the surface of the frame 31, the region 36 on the main storage portion 35 side is a seal region storage portion that is slightly recessed as compared to the region 32 outside. A pair of tab seal portion storage portions 37 that are slightly recessed are formed in the seal region storage portion 36 along one short side of the pair of short sides of the frame 31. A pair of tab storage portions 38 that are slightly recessed are formed in the outer region 32 along the short side. The tab seal portion storage portion 37 and the tab storage portion 38 are continuous and cross the short side.

  At the four corners of the outer region 32 of the frame 31, through holes 33 that penetrate the frame 31 in the thickness direction (Z-axis direction) are formed. Further, a pair of screw holes (female screws) 34 are formed in the outer surface 31 s adjacent to the tab storage portion 38 of the frame 31.

  The bottom surface of the main storage part 35 is composed of a plurality of strip plates 41 arranged in parallel to each other along the Y-axis direction. The plurality of strip plates 41 are arranged at a constant pitch in the X-axis direction and spaced apart from each other, and form a stripe shape as a whole. As shown in FIG. 4D, a slot-like opening 43 is formed between adjacent strip plates 41. The number of the strip plates 41 and the pitch thereof can be arbitrarily set.

  As shown in FIGS. 4B and 4C, a plurality of ridges 42 and a plurality of ridges 44 are alternately arranged on the back surface of the frame 31 in the X-axis direction. The ridges 42 are rib-shaped (ridge-shaped) projections parallel to the Y-axis direction, and are formed in a region extending from the strip plate 41 in the Y-axis direction. The top surface of the ridge 42 and the top surface of the strip plate 41 constitute substantially the same surface. The concave stripe 44 is a groove parallel to the Y-axis direction, and is formed in a region extending from the opening 43 in the Y-axis direction.

  4A to 4D, an alternate long and short dash line 30a is a plane (center plane) parallel to the YZ plane passing through the center position of the case 30 in the X-axis direction. As can be easily understood from these drawings, the storage portions 35, 36, 37, and 38 are symmetrical with respect to the central surface 30 a, while the strip plate 41, the ridge 42, the opening 43, and the recess 44 are It is not symmetrical with respect to the center plane 30a. The center surface 30a passes through the boundary between the strip plate 41 (projection 42) and the opening 43 (concave 44).

  The material of the case 30 is not limited, but an insulating resin material can be used. The case 30 can be integrally formed using such a resin material by an injection molding method or the like.

  As shown in FIG. 5, the battery cell 10 is housed (inserted) in the case 30 with the convex portion 15 (see FIG. 1A) facing the surface of the case 30. The convex portion 15 and the seal region 16 (see FIG. 1A) of the battery cell 10 are stored in the main storage portion 35 and the seal region storage portion 36 of the case 30, respectively. The tab seal portions 17p and 17n (see FIG. 1A) of the battery cell 10 are housed in the tab seal portion housing portion 37 of the case 30. The electrode tabs 11p and 11n of the battery cell 10 are stored in the tab storage portion 38 of the case 30. The depths of the main storage portion 35, the seal region storage portion 36, the tab seal portion storage portion 37, and the tab storage portion 38 with respect to the outer region 32 of the frame 31 are respectively the convex portion 15, the seal region 16, and the tab seal portion 17p stored therein. , 17n and the electrode tabs 11p, 11n are set to be substantially the same in thickness. When the battery cell 10 is housed in the case 30, the surface (back surface) opposite to the convex portion 15 of the battery cell 10 forms a substantially same plane as the outer region 32 of the case 30.

  A plurality of cases 30 each storing the battery cells 10 are laminated with the front and back being alternately inverted so that every other battery cell 10 is turned over as shown in FIG. FIG. 6 is an exploded perspective view of a unit 23 configured by laminating two cases 30 each housing the battery cell 10. In the unit 23, the case 30 is laminated with the surfaces thereof facing each other.

  In order to ensure insulation between the two battery cells 10 more reliably, an insulating sheet 50 may be provided between the battery cells 10. For example, even when the laminate sheet 13 of the battery cell 10 has an insulating layer formed on the outer surface of a base layer made of aluminum, a short circuit may occur if a slight scratch is formed on the insulating layer. It is. The insulating sheet 50 has a substantially rectangular shape that is substantially the same as the outer shape of the case 30 (or the frame 31). The outer peripheral edge of the insulating sheet 50 is sandwiched between the outer regions 32 of the frames 31 of the two cases 30. An insulating tab 51 protrudes from the short side of the insulating sheet 50. The insulating tab 51 faces one of the pair of electrode tabs 11p, 11n of the battery cell 10. The through holes 52 are formed at the four corners of the insulating sheet 50. The position of the through hole 52 corresponds to the position of the through hole 33 of the case 30.

  The battery cell 10 is held in the case 30 by being fitted into the storage portions 35, 36, 37, and 38 (see FIG. 3) of the case 30. The depth of the tab storage portion 38 is set so that the electrode tabs 11p, 11n of the battery cell 10 are compressed and sandwiched by the tab storage portion 38 of the case 30 when the two battery cells 10 are overlapped. It is preferable. Thereby, even if the battery cell 10 is temporarily displaced in the case 30 due to vibration or impact, the influence of the displacement of the battery cell 10 on the electrode tabs 11p and 11n derived from the case 30 can be reduced. As a result, it is possible to reduce the occurrence of breakage or damage to the electrode tabs 11p, 11n in a state where the electrode tabs 11p, 11n are connected to the circuit board 60 as described later (see FIG. 14).

  The convex portion 15 in which the power generation element of the battery cell 10 is built is housed in the main housing portion 35 of the case 30. The bottom surface of the main storage portion 35 is composed of a plurality of strip plates 41 spaced apart from each other. Since the battery cell 10 can be cooled or kept warm through the opening 43 between the strip plates 41, the temperature of the battery cell 10 can be appropriately maintained. Further, the battery cell 10 accommodated in the case 30 can be visually recognized through the opening 43.

  Compared with the case where the bottom surface of the main storage portion 35 is formed of a continuous plate material in which the opening 43 is not formed, the strength of the bottom surface of the main storage portion 35 of the present embodiment configured with a plurality of strip plates 41 is as follows. Relatively weak. Accordingly, the plurality of strip plates 41 can deform and absorb the dimensional error of the battery cell 10 by itself. Further, when the battery cell 10 swells due to generation of gas in the laminate seal 13, the plurality of strip plates 41 can be appropriately deformed according to the swell. Therefore, when a gas abnormality occurs in the battery cell 10, the battery cell 10 can be easily expanded to suppress an abnormal increase in pressure in the battery cell 10, and the abnormal expansion of the battery cell 10 can be suppressed. It can be determined relatively easily from the external shape of the laminate 20 (see FIG. 13 described later).

  Furthermore, as compared with the case where all of the plurality of strip plates 41 are removed and the entire region surrounded by the frame 31 is opened, the plurality of strip plates 41 bridged to the opening of the frame 31 has the convex portions 15 of the battery cells 10. Since it is held, the battery cell 10 is stably held in the case 30. This improves the handleability of the battery cell 10 in the process of manufacturing the battery stack 20 (see FIG. 13 described later) by sequentially stacking the battery cells 30 containing the battery cells 10. Accordingly, the battery stack 20 can be easily manufactured.

  Bolts 22 as connecting members for connecting the case 30 are inserted into the through holes 33 of the case 30 (see FIG. 13 described later). When the sealing region 16 protrudes from the sealing region storage portion 36 due to a positional deviation of the battery cell 10 with respect to the case 30 or a dimensional error of the sealing region 16, the laminate sheet 13 that covers the battery cell 10 contacts the bolt 22. May cause a short circuit. A structure for preventing this may be provided in the case 30. An example of the structure will be described with reference to FIG. FIG. 7 is an enlarged cross-sectional view of the through hole 33 along the plane including the line 7-7 in FIG. 4A. The edge of the opening on the surface side of one of the two through holes 33 (the right side through hole in FIG. 7) of the two through holes 33 formed in the vicinity of both ends of the short side of the case 30 is compared to the surrounding area. An annular projecting portion 331 that protrudes in this manner is formed. At the edge of the opening on the surface side of the other through-hole (the left-side through-hole in FIG. 7) 33, an annular recess 332 is formed that is recessed as compared with the peripheral region. Although not shown, convex portions 331 and depressions 332 similar to those in FIG. 7 are also formed on the surface side edges of the openings of the two through holes 33 formed in the vicinity of both ends of the other short side of the case 30. Has been. As shown in FIG. 6, when the two cases 30 are overlapped, the protrusion 331 of one case 30 fits into the recess 332 of the other case 30. Therefore, even if the seal region 16 of the battery cell 10 protrudes from the seal region storage portion 36, the protrusion 331 prevents the seal region 36 from coming into contact with the bolt 22 inserted into the through hole 33. As a result, the possibility of a short circuit accident is reduced. The fitting between the protrusion 331 and the recess 332 also has an effect of reducing the positional deviation between the two cases 30. The through hole 52 of the insulating sheet 50 is set to a size that allows the protrusion 331 to pass therethrough. The protrusion 331 also has a secondary effect of positioning the insulating sheet 50 with respect to the case 30. Note that the protrusion 331 and the recess 332 do not have to be annularly continuous along the edge of the opening of the through hole 33. Further, the protrusion 331 and the recess 332 shown in FIG. 7 are optional, and these can be omitted.

  Protrusions and depressions similar to the above-described protrusions 331 and depressions 332 may be formed at the edge of the opening on the back side of the through hole 33. In this case, when two cases 30 (for example, a case 30a and a case 30b in FIG. 9 to be described later) are overlapped with the back surfaces facing each other, a protrusion and a recess formed on the back surface side are fitted. Thereby, the position shift between the two cases 30 can be reduced.

  FIG. 8 is a perspective view of a unit laminate 25 in which the two units 23 shown in FIG. 6 are laminated. The electrode tabs 11p and 11n of each of the two battery cells 10 and the insulating tab 51 protrude from between the two cases 30 constituting each unit 23.

  FIG. 9 is a cross-sectional view of the unit stacked body 25 along a plane parallel to the stacking direction including line 9-9 in FIG. In the following description, when it is necessary to distinguish between the two units 23 and the members constituting each, the suffixes “a” or “b” are added to the reference numerals of the members to distinguish them. In FIG. 9, the upper unit 23a and the lower unit 23b that are actually in contact with each other are slightly separated from each other for easy understanding.

  The two units 23a and 23b are stacked with the back surface of the lower case 30a of the unit 23a and the back surface of the upper case 30b of the unit 23b facing each other. More specifically, the opening 43b of the case 30b faces the strip plate 41a of the case 30a, and the strip plate 41b of the case 30b faces the opening 43a of the case 30a. Therefore, when the unit 23a and the unit 23b are stacked, the strip plate 41 of one of the case 30a and the case 30b is fitted into the opening 43 of the other case. Although illustration is omitted, similarly, the protrusion 42 of one of the case 30a and the case 30b fits into the recess 44 of the other case.

  As described above, when the two cases 30 are overlapped with their back surfaces facing each other, the strip plate 41 and the opening 43 of one case 30 are fitted to the opening 43 and the strip plate 41 of the other case 30, respectively. The ridges 42 and the ridges 44 of one case 30 are fitted into the ridges 44 and the ridges 42 of the other case 30. The distance between the battery cells 10a and 10b housed in the cases 30a and 30b substantially matches the thickness of one layer of the strip plate 41, respectively. Therefore, in the present embodiment, it is possible to reduce the overall thickness of the unit laminate 25 as compared to the case where the bottom surface of the main storage portion 35 is formed of a continuous plate material having a constant thickness where the opening 43 is not formed. it can. This is advantageous for miniaturization of the battery stack 20 (see FIG. 13) and the battery pack 70 (see FIG. 15) to be finally obtained. Therefore, a reduction in mounting efficiency due to the battery cell 10 being housed in the case 30 can be suppressed.

  Further, when the bottom surface of the main storage portion 35 does not exist (that is, when all of the plurality of strip plates 41 are removed), in order to ensure insulation between the adjacent battery cells 10a and 10b, between the units 23a and 23b. In addition, it is necessary to provide the insulating sheet 50. In the present embodiment, the opening 43 of one case 30 is substantially blocked by the strip plate 41 of the other case 30, so even if the insulating sheet 50 is not provided, the space between the battery cell 10 a and the battery cell 10 b is not provided. Insulation can be ensured. Thus, in this embodiment which does not need to provide the insulating sheet 50 between the adjacent units 23, the number of required insulating sheets is reduced by half compared with the case where all the battery cells 10 are stacked with an insulating sheet interposed. be able to. This is advantageous in facilitating the manufacture and size reduction of the battery stack 20 (see FIG. 13) and the battery pack 70 (see FIG. 15). Moreover, since the insulating sheet of the battery cell is required to have flame retardancy, it is generally expensive. Therefore, reducing the number of insulating sheets is advantageous in reducing the cost of the battery stack 20 and the battery pack 70.

  As described with reference to FIGS. 4A to 4D, the strip plate 41, the ridge 42, the opening 43, and the dent 44 of the case 30 are disposed asymmetrically with respect to the central surface 30 a. As a result, when the case 30 having the same shape is stacked with its back surfaces facing each other, the strip plate 41 and the opening 43 are fitted between the two adjacent cases 30 as described above, and the ridge 42 and the recess 44 is fitted. As described above, in this embodiment, a single type of case having the same shape is used as the plurality of cases 30 constituting the battery stack 20 (see FIG. 13). Therefore, when assembling the battery stack 20, it is not necessary to consider the difference in the shape of each case 30, so that the assembly can be performed easily and efficiently. In addition, since the case 30 can be mass-produced by injection molding or the like using a single molding die, the battery laminate 20 can be reduced in cost.

  In order to monitor the temperature of the battery cell 10, a temperature detection element can be provided. FIG. 10 is an exploded perspective view for explaining a method for attaching the temperature detecting element 55. A slit-like cutout 53 is formed in the insulating sheet 50. The temperature detection element 55 is inserted into the notch 53. Then, the insulating sheet 50 and the temperature detection element 55 in the notch 53 are sandwiched between the two cases 30. It is preferable that the insulating sheet 50 and the temperature detection element 55 have substantially the same thickness. If necessary, the insulating sheet 50 into which the temperature detecting element 55 is inserted has the same thickness as the temperature detecting element 55, and the insulating sheet 50 has a different thickness from the other insulating sheets 50 (for example, A material thicker than other insulating sheets 50) may be used.

  As in this embodiment, by inserting the temperature detection element 55 into the notch 53 formed in the insulating sheet 50, the insulation between the adjacent battery cells 10 is ensured and the thickness of the battery stack 20 is increased. While being suppressed, the temperature detection element 55 can be provided at a necessary location.

  In FIG. 10, the notch 53 has a slit shape, but the shape of the notch 53 is not limited to this, and can be appropriately changed to match the shape of the temperature detection element 55. The number of temperature detection elements 55 provided in the battery stack is arbitrary. A notch 53 is formed as shown in FIG. 10 and the temperature detecting element 55 is inserted only in the insulating sheet 50 at a position where the temperature detecting element 55 needs to be provided among the plurality of insulating sheets 50 constituting the battery stack. do it.

  In order to suppress the temperature rise of the battery cell 10, a heat radiating plate may be provided between the adjacent cases 30 (that is, between the adjacent battery cells 10). FIG. 11A is a perspective view of the unit laminate 25 to which the heat sinks 57a and 57b are attached. FIG. 11B is a cross-sectional view of the unit laminate body 25 along the plane including the line 11B-11B in FIG. 11A. As the heat radiating plates 57a and 57b, a thin plate material of a metal (for example, aluminum, copper, etc.) excellent in heat transfer characteristics can be used. In order to impart insulation to the heat radiating plates 57a and 57b, an insulating paint may be applied to both surfaces of the heat radiating plates 57a and 57b, or an insulating sheet may be attached as necessary.

  In the present embodiment, the heat radiating plate 57a thus provided with insulation is used instead of the insulating sheet 50 (see FIG. 6). The heat radiating plate 57 a is provided with a tab similar to the insulating tab 51 provided on the insulating sheet 50. Further, a heat radiating plate 57 b is provided between the units 23. Accordingly, all the cases 30 (battery cells 10) are adjacent to each other through the heat dissipation plate 57a or 57b. Although illustration is omitted, through holes are formed at positions of the heat radiating plates 57a and 57b corresponding to the through holes 33 of the case 30.

  Radiating plates 57 a and 57 b protrude from both side surfaces along the long side of the case 30. The protruding portions of the heat radiating plates 57a and 57b can function as heat radiating fins. Alternatively, the protruding portions of the heat radiating plates 57a and 57b may be brought into contact with another member (for example, the inner surface of the battery pack casing) to promote heat conduction.

  FIG. 11C is an enlarged cross-sectional view of a portion 11C including the heat dissipation plate 57b of FIG. 11B. The heat radiating plate 57b is deformed in a zigzag shape (wave shape) so as to sew between the strip plates 41 of the two cases 30. Since the heat radiating plate 57b is deformed in this manner, an increase in the distance between the two cases 30 due to the provision of the heat radiating plate 57b can be suppressed. This is advantageous in reducing the size of the battery stack 20 (see FIG. 13) and the battery pack 70 (see FIG. 15). Since the heat sink 57b has insulation, insulation between two adjacent battery cells 10 is ensured through the heat sink 57b. By appropriately setting the width of the strip plate 41, a gap 58 is formed between the strip plate 41 and the heat radiating plate 57b. The gap 58 continues in a direction perpendicular to the paper surface of FIG. 11C and communicates with the outside of the case 30. Therefore, air flows into the gap 58, and the battery cell 10 can be cooled thereby. As a result, the cooling efficiency is further improved.

  In addition, in FIG. 11A-FIG. 11C, although the heat sink was arrange | positioned between all the adjacent battery cells 10, this invention is not limited to this. For example, in FIGS. 11A and 11B, one of the heat radiating plate 57a and the heat radiating plate 57b can be omitted. A heat sink having no insulating property can also be used. In that case, you may arrange | position an insulating sheet on both sides of a heat sink as needed.

  The electrode tabs 11p and 11n of each battery cell 10 are connected so that the plurality of battery cells 10 are connected in series as shown in FIG. In FIG. 8, a method of connecting the electrode tabs 11p and 11n protruding from the case 30 will be described with reference to FIG.

  In FIG. 12, among the opposing electrode tabs 11p and 11n opposite to each other that protrude from between the two cases 30 constituting each unit 23, the electrode tabs 11p and 11n on the back side are overlapped with each other, and the tip portion thereof is It is folded back to the case 30 side.

  On the other hand, the front electrode tabs 11p and 11n sandwiching the insulating tab 51 (see FIG. 6) are bent at the first bent portion 111 so as to be separated from each other, and the second is farther from the case 30 than the first bent portion 111. The bent portion 112 is bent in the opposite direction to the first bent portion 111. The bending angle of the electrode tabs 11p and 11n at the first bent portion 111 and the second bent portion 112 (defined based on the straight state before the bending) is about 90 degrees in FIG. It is not limited to this, Preferably it can set arbitrarily at 90 degrees or less. The bent shape of the electrode tabs 11p and 11n sandwiching the insulating tab 51 is substantially symmetric with respect to the plane including the insulating tab 51. The tip portions of the bent electrode tabs 11p and 11n (the portion above the second bent portion 112) are overlapped with the tip portions of the electrode tabs having different polarities protruding from the adjacent unit 23. The tip 51t of the insulating tab 51 extends farther than the first bent portion 111 and closer to the tip of the electrode tabs 11p and 11n when viewed from the case 30. That is, the electrode tabs 11p and 11n are bent away from each other at the first bent portion 111 closer to the case 30 than the tip 51t of the insulating tab 51. By bending the electrode tabs 11p and 11n having different polarities facing each other through the insulating tab 51 in this way, the length of the protrusion of the insulating tab 51 from the case 30 can be increased while ensuring the insulation between the electrode tabs 11p and 11n. Can be small. Thereby, the area of the insulating sheet 50 can be reduced. Moreover, when the insulating sheet 50 is cut out from, for example, a long original sheet, the area of the original sheet that is discarded without being used can be reduced, so that the utilization efficiency of the original sheet is improved. Therefore, shortening the protruding length of the insulating tab 51 from the case 30 is advantageous for cost reduction.

  Although only two units 23 are shown in FIG. 12, when more units 23 are stacked, the electrode tabs 11p and 11n are processed in the same manner as in FIG. 12 (see FIG. 13 described later). .

<Battery laminate>
FIG. 13 is a perspective view of the battery stack 20 according to one embodiment of the present invention. The battery stack 20 includes 14 cases 30 each containing the battery cells 10. The fourteen cases 30 are laminated with their front and back being alternately inverted. The through holes 33 (see FIG. 3) formed at the four corners of each case 30 form four continuous holes in the stacking direction. A dimension bolt 22 is inserted as a connecting member into the continuous hole, and nuts 23 are fastened to both ends thereof. Thereby, the 14 cases 30 are connected and firmly integrated. The dimensioning bolt 22 reduces the positional deviation of each battery cell 22. The accuracy of the outer dimensions of the battery stack 20 is good regardless of the dimensional error of each battery cell 10.

  The battery stack 20 is manufactured by sequentially stacking the cases 30 containing the battery cells 10 by turning over the other cases 30. At this time, the insulating sheet 50 (see FIG. 6) and / or the heat sinks 57a and 57b (see FIGS. 11A and 11B) are inserted between the cases 30 as necessary. A unit 23 (see FIG. 6) in which two cases 30 are stacked may be created in advance, and the units 23 may be sequentially stacked. After the necessary number of cases 30 are stacked, the case 30 is integrated with the dimensioning bolts 22 and the nuts 23.

  In the manufacturing operation of the battery stack 20, the battery cell 10 covered with the flexible laminate sheet 13 can be handled in a state of being housed in the hard case 30. Thereby, since the handleability of the laminate-type battery cell 10 which is easily deformed is improved, the battery stack 20 can be easily manufactured. In addition, since the case 30 can be accurately positioned on the outer surface of the case 30, the battery cell 10 can be easily and accurately compared to a conventional battery stack manufactured by positioning in the seal region 16 of the battery cell 10. Can be positioned. Thereby, manufacture of the battery laminated body 20 becomes still easier, and the assembly precision of the battery laminated body 20 obtained improves.

  The plurality of cases 30 are connected by inserting the connecting member 22 into the through hole 33. This makes it much easier to manufacture the battery laminate 20 and improves the connection strength than the conventional method of integrating adjacent battery cells using a double-sided adhesive tape. Further, when it is necessary to disassemble the integrated battery stack 20 for some reason, each battery cell 10 can be easily taken out without being damaged.

  The number of battery cells 10 and cases 30 constituting the battery stack 20 can be arbitrarily set. For example, the battery stack can be configured by the unit stack 25 including the four cases 30 shown in FIG. The length of the cutting bolt 22 can be appropriately changed according to the number of cases 30 constituting the battery stack 20. Both outer side surfaces of the battery stack 20 in the stacking direction are preferably the back surfaces of the case 30 as shown in FIG.

  The connecting member inserted into the through hole 33 of the case 30 is not limited to the dimension bolt 22, and a known screw member such as a hexagon bolt may be used.

  FIG. 14 is a perspective view of the battery stack 20 to which the circuit board 60 is attached. The circuit board 60 is fixed to the battery stack 20 via four board bonding members 68. The substrate bonding member 68 is fixed to the four corners of the upper surface of the battery stack 20 by fastening bolts to the screw holes 34 (see FIG. 13) formed in the frame 31. In the present invention, since the battery cell 10 is housed in the case 30, the circuit board 60 can be fixed to the frame 31 of the case 30.

  The superposed electrode tabs 11p and 11n (see FIG. 12) and the input / output tabs 11p ′ and 11n ′ (see FIG. 2) pass through a slot-like tab insertion hole 61 formed in the circuit board 60. Yes. The electrode tabs 11p, 11n, 11p ', 11n' protruding upward through the circuit board 60 are soldered to a wiring pattern (not shown) formed on the upper surface of the circuit board 60. Compared with the method of connecting the electrode tabs 11p, 11n, 11p ′, 11n ′ and the circuit board 60 with conductive wires, the electrode tabs 11p, 11n, 11p ′, 11n ′ penetrating the circuit board 60 are soldered to the circuit board 60. The method of this embodiment to be attached can greatly simplify the process of electrically connecting the electrode tabs 11p, 11n, 11p ′, 11n ′ and the circuit board 60.

  Since the circuit board 60 is fixed to the battery stack 20, the relative position of the circuit board 60 with respect to the battery stack 20 is constant. Therefore, even if vibration or impact is applied, there is a low possibility that troubles such as breakage of the solder or breakage of the electrode tabs 11p, 11n, 11p ', 11n' occur. In addition, the possibility that the battery stack 20 collides with the circuit board 60 to break or damage the circuit board 60 is low. Therefore, the battery stack 20 has high reliability.

  Although not shown, the circuit board 60 has a voltage monitoring circuit for monitoring the voltage of each battery cell 10, a temperature monitoring circuit for monitoring the temperature of the battery cell 10, and a current between the external device connected to the battery pack. A device that constitutes an arbitrary circuit such as a protection circuit or a control circuit necessary for the battery pack, such as a current monitoring circuit for monitoring the battery pack or a control circuit that cuts off the continuity with an external device when an abnormality is detected, can be mounted.

  The fixing method of the circuit board 60 using the screw hole 34 is not limited to FIG. For example, the circuit board 60 can be fixed to the battery stack 20 by fastening a bolt penetrating the circuit board 60 from above into the screw hole 34. In order to separate the circuit board 60 and the battery stack 20, a spacer (for example, a cylindrical object that is penetrated by the bolt) can be interposed between the two as necessary.

  Various electrical wirings (harnesses) and various parts may be further attached to the battery stack 20 using the screw holes 34 provided in the case 30. Thereby, by applying vibration and impact, it is possible to prevent the circuit board 60 and the like from being damaged or damaged by collision of these wirings or components with the battery stack 20 or the circuit board 60.

<Battery pack>
FIG. 15 is a cross-sectional view of a battery pack 70 in which the battery stack 20 shown in FIG. In FIG. 15, the battery stack 20 and the circuit board 60 are shown as side views rather than sectional views. The casing 72 is a sealed container having a substantially rectangular parallelepiped shape. The battery stack 20 is held in the casing 72 via a buffer member 74 fixed to the casing 72. The distances D1, D2, and D3 between the circuit board 60 and the housing 72 are larger than the thickness of the buffer member 72. Therefore, even if the shock is applied to the battery pack 70 by dropping the battery pack 70 or the like, and the thickness of the buffer member 74 becomes zero, the circuit board 60 does not collide with the inner wall of the housing 72. Further, since the circuit board 60 is fixed to the battery stack 20 instead of the casing 72, the circuit board 60 and the battery stack 20 do not collide. Therefore, the circuit board 60 is not broken or damaged. In addition, since the battery cell 10 is housed in the case 30, the battery cell 10 does not collide with the inner wall of the housing 72 to be damaged or damaged.

  In a conventional battery pack, the circuit board is generally fixed to a housing instead of a battery stack. In this configuration, there is a possibility that an accident in which a heavy battery stack is displaced in the housing and collides with the circuit board due to vibration or impact. The battery pack 70 of the present invention has a reduced possibility of such an accident, is excellent in impact resistance, and has high reliability.

  The above embodiments are merely exemplary. The present invention is not limited to the above embodiment, and can be modified as appropriate.

  In the above embodiment, the plurality of strip plates 41 of the case 30 are parallel to the long sides of the case 30, but the present invention is not limited to this. For example, the plurality of strip plates 41 may be parallel to the short side of the case 30, or may be non-parallel to both the long side and the short side (that is, the long side and the short side). May be inclined). Regardless of the orientation of the strip plate 41, the ridge 42 and the recess 44 are always parallel to the strip plate 41.

  In the above embodiment, the ridges 42 and the ridges 44 are formed on the back surface of the frame 31 of the case 30, but the present invention is not limited to this. If the strips 41 of one case 30 can be inserted into the opening 43 of the other case 30 when the two cases 30 are stacked with their back surfaces facing each other, the ridges 42 and the ridges 44 are omitted. In addition, the back surface of the frame 31 may be configured as a flat surface without any unevenness.

  The field of application of the present invention is not particularly limited, and battery stacks and batteries used as power sources for various mobile devices such as automobiles, motorcycles, and electrically assisted bicycles, personal digital assistants, uninterruptible power supplies (UPS), and power storage devices. Can be used widely as a pack.

10 battery cell 11p positive electrode tab (electrode tab)
11n Negative electrode tab (electrode tab)
111 First bent portion 112 Second bent portion 13 Laminate sheet (sheet)
15 Convex 16 Seal Area 20 Battery Stack 22 Dimensional Bolt (Connecting Member)
30 Case 31 Frame 31s Frame outer surface 33 Through-hole 331 Projection (protrusion)
332 Depression (Depression)
34 Screw hole 35 Main storage portion 36 Seal region storage portion 41 Strip plate 43 Opening 50 Insulation sheet 51 Insulation tab 51t Insulation tab tip 53 Insulation sheet notch 55 Temperature detection element 57a, 57b Heat sink 60 Circuit board 70 Battery pack 72 Enclosure

Claims (13)

A battery laminate including a plurality of thin plate-like battery cells and a plurality of cases each housing the plurality of battery cells,
Each of the plurality of battery cells includes a flexible sheet for covering the power generation element,
A sealing region in which the sheet is sealed is formed along the outer periphery of the battery cell,
On one side of the battery cell, a convex portion due to the power generation element protrudes with respect to the seal region,
Each of the plurality of cases includes a frame in which a seal region storage portion for storing the seal region of the battery cell is formed on a surface thereof, and a main storage that is surrounded by the frame and stores the convex portion of the battery cell. With
The bottom surface of the main storage portion is composed of a plurality of strip plates arranged in parallel and spaced apart from each other, and an opening is formed between adjacent strip plates.
The plurality of cases are laminated with the front and back being alternately inverted,
The plurality of strip plates of one case of two cases adjacent to each other with the back surfaces opposite to the front surface on which the seal region storage portion is formed are A battery laminate, wherein the battery stack is fitted into a plurality of openings between the plurality of strip plates.   The battery stack according to claim 1, wherein the plurality of battery cases all have the same shape. A through hole is formed in each of the frames of the plurality of cases;
The through hole forms a continuous hole continuous in the stacking direction of the plurality of cases,
The battery stack according to claim 1 or 2, wherein a connecting member inserted into the continuous hole connects the plurality of cases. The edge of the opening on the surface side of the through hole protrudes or is depressed compared to the peripheral region,
The protrusion formed at the edge of the opening of one case of the two cases facing each other and facing each other is inserted into the depression formed at the edge of the opening of the other case. The battery laminate according to claim 3.   The battery laminate according to any one of claims 1 to 4, wherein an insulating sheet is provided between two battery cells adjacent to each other with the surfaces opposite to the convex portions facing each other. A temperature detection element for detecting the temperature of the battery cell;
The battery stack according to claim 5, wherein the temperature detection element is inserted into a notch formed in the insulating sheet. Each of the plurality of battery cells includes a pair of electrode tabs,
One electrode tab of the pair of electrode tabs of one of the two battery cells adjacent to each other across the insulating sheet is electrically connected to the electrode tab facing the one electrode tab of the other battery cell. The other electrode tab of the one battery cell and the electrode tab facing the other electrode tab of the other battery cell from each other at the first bent portion outside the case. Bent away from the first bent portion and bent in a direction opposite to the first bent portion at a second bent portion farther from the case than the first bent portion;
The portion of the insulating sheet that protrudes from the case between the other electrode tab and the electrode tab that faces the other electrode tab is farther than the first bent portion and the other electrode tab. 7. The battery stack according to claim 5, wherein the battery stack extends to a position closer to the tip and the tip of the electrode tab facing the other electrode tab.   The battery laminate according to any one of claims 1 to 7, wherein a heat radiating plate is provided between the adjacent cases. The heat sink is provided between the two cases that are adjacent to each other with their back surfaces facing each other,
The battery stack according to claim 8, wherein the heat radiating plate is deformed in a zigzag shape and disposed between the plurality of strip plates of the two cases. Furthermore, a circuit board is provided,
The battery stack according to claim 1, wherein the circuit board is fixed to the frame of the case.   The battery laminated body according to claim 10, wherein a screw hole for fixing the circuit board is formed on an outer surface of the frame.   The battery laminate according to claim 10 or 11, wherein an electrode tab led out from the battery cell is soldered to the circuit board.   The battery pack provided with the battery laminated body in any one of Claims 1-12, and the housing | casing which accommodates the said battery laminated body.

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