JP7301271B2 - battery pack - Google Patents

Description

The present invention relates to a battery pack containing a plurality of battery cells.

In recent years, from the viewpoint of saving resources and energy, there is an increasing demand for secondary batteries such as nickel-metal hydride, nickel-cadmium, and lithium-ion batteries that can be used repeatedly. Among them, the lithium-ion secondary battery is characterized by its light weight, high electromotive force, and high energy density. For this reason, the demand for power sources for driving various types of portable electronic devices and mobile communication devices such as mobile phones, digital cameras, video cameras, and notebook personal computers is increasing.

On the other hand, along with miniaturization and high energy density, there is a risk of heat generation to high temperatures depending on the usage. Therefore, the safety of batteries and battery packs has become more important.

For example, the batteries described above may generate gas internally if they are overcharged, overdischarged, or short-circuited internally or externally. The gas thus generated increases the internal pressure of the battery. If such a situation occurs, there is a possibility that the outer can will burst due to the increase in internal pressure. In order to prevent such explosion, these batteries are provided with an exhaust hole for gas release, a safety valve, and the like.

Also, in a battery pack containing such batteries in a housing, a structure has been proposed in which the gas is discharged to the outside of the housing in order to improve safety. Furthermore, in a state in which such gas is generated, there is a possibility that smoke or fire may occur in the battery pack due to the influence of, for example, an overheated battery.

A battery pack has been proposed that effectively prevents the spread of fire in a plurality of batteries while suppressing the influence of ejecting bodies such as high-temperature gas and flame ejected from the battery on the outside of the battery pack (for example, Patent Document 1). As shown in FIG. 10, this battery pack has a plurality of battery cells 1 formed by closing the opening of a cylindrical outer can 11 with a sealing plate with a sealing plate, and the plurality of battery cells 1 are arranged in parallel to each other. Also, a battery holder 2 that holds the electrode terminals provided at both ends of each battery cell 1 on the same plane, and an exterior housing a battery assembly 10 in which a plurality of battery cells 1 are held by the battery holder 2 A case 4 is provided. The battery holder 2 includes a holding portion 6 that holds the ends of the plurality of battery cells 1 along the outer peripheral surface of the outer can 11, and a covering portion that covers the end surfaces of the plurality of battery cells 1 held by the holding portion 6. 7, and when the battery cell 1 malfunctions, the energy of the ejector ejected from the end face of the battery cell 1 changes the quality of the covering portion 7. As shown in FIG.

Republished publication 2017-130259

However, between adjacent battery cells, for example, when high-temperature gas is discharged from one battery cell, the gas is exposed to the electrode surface of another adjacent battery cell with the electrode surface of this battery cell being on the same plane. As a result, there was a possibility that it would be heated and spread.

One object of the present invention is to provide a battery pack that can effectively prevent the spread of fire in a plurality of batteries while suppressing the effects of ejecting bodies such as high-temperature gas ejected from batteries and flames when ignited. .

A battery pack according to one aspect of the present invention comprises: a plurality of battery cells provided with electrode terminals on end faces extending in a first longitudinal direction and a safety valve provided on at least one end face; A battery holder is provided that holds the electrode terminals provided at both ends of each battery cell in a posture parallel to each other in the first longitudinal direction and in a posture that arranges the electrode terminals on the same plane. The battery holder includes: an end holding portion holding an end portion having one or more safety valves of the plurality of battery cells; and a battery stacked and fixed to the end holding portion and held by the end holding portion. a cell covering portion that covers the end face side of the cell, the end holding portion having a plurality of recesses in which lead plates that connect electrode terminals of adjacent battery cells are arranged, respectively; An insulating wall for insulating the lead plates is provided at a boundary portion between the recesses, and the battery holder includes the plurality of recesses in the end holding portion and an outlet for communicating with the outside of the battery holder . It is formed on the side surface along one longitudinal direction.

According to the battery pack according to one aspect of the present invention, even if any of the battery cells ejects the ejecting body, the ejecting body can be ejected to the outside of the battery pack through the ejection port opened in the side surface of the battery holder. Therefore, it is possible to avoid exposing adjacent battery cells to the high temperature and high pressure of the ejector, thus improving safety.

1 is a perspective view showing a battery pack according to Embodiment 1; FIG. FIG. 2 is a side view of the battery pack of FIG. 1; FIG. 2 is a front view of the battery pack of FIG. 1; FIG. 3 is a vertical cross-sectional view of the battery pack of FIG. 2 taken along line IV-IV; FIG. 2 is an exploded perspective view of the battery pack of FIG. 1; 6 is a further exploded perspective view of the battery pack of FIG. 5; FIG. FIG. 8 is a perspective view of a battery pack according to Embodiment 2; FIG. 11 is an exploded perspective view of a battery pack according to Embodiment 3; FIG. 11 is an exploded perspective view of a battery pack according to Embodiment 4; FIG. 11 is an exploded perspective view showing a conventional battery pack;

A battery pack according to one aspect of the present invention may be configured as follows in addition to the configuration described above.

In the battery pack according to one embodiment of the present invention, the plurality of battery cells have a cylindrical outer shape, and the battery holder holds the plurality of battery cells held in a parallel posture, and each electrode terminal is arranged in a matrix. and holding both end faces in the first longitudinal direction in a rectangular shape corresponding to the matrix, and corners of the rectangular shape are chamfered along the cylindrical end faces of the battery cells. The discharge port includes a corner discharge port opened in a curved shape at a chamfered corner portion on the side surface of the battery holder. With the above configuration, compared to the case where the discharge port is opened in a slit shape at the rectangular corner of the battery holder, the corner discharge port is continuously opened at the chamfered corner of the battery holder, so that the rectangular corner can be formed. This provides the advantage of avoiding the accumulation of high-pressure ejected bodies in the parts and smoothly discharging the ejected bodies from the battery cells to the outside with less resistance.

In a battery pack according to another embodiment of the present invention, the battery holder has a rectangular shape obtained by extending the rectangular shapes of both side end surfaces in the first longitudinal direction in a second longitudinal direction that intersects the first longitudinal direction. and the outlet includes an intermediate outlet opened in the middle of the second longitudinal direction on the side surface of the battery holder. With the above configuration, the intermediate discharge port can be opened between the corner discharge ports to further improve the discharge performance of the jetting body.

Further, in a battery pack according to another embodiment of the present invention, each of the plurality of battery cells is provided with the safety valve on the positive electrode side of the electrode terminal, and the battery holder is provided with the safety valve on the electrode terminal of the plurality of battery cells. The discharge port is opened on the positive electrode side. With the above configuration, the ejection body discharged from the safety valve provided on the positive electrode side of the battery cell can be efficiently discharged to the outside of the battery pack from the discharge port opened on the positive electrode side.

Furthermore, in a battery pack according to another embodiment of the present invention, the battery holder opens the outlet for each positive electrode of the electrode terminals of the plurality of battery cells.

Furthermore, in a battery pack according to another embodiment of the present invention , the battery holder has, on a surface facing the cell covering portion, a gap closing wall that protrudes toward the cell covering portion so as to abut against the cell covering portion. ing. With the above configuration, by providing a gap blocking wall between adjacent battery cells, even if high-temperature gas is discharged from one battery cell, the gas is discharged from the end face side of the other adjacent battery cell. It is possible to prevent the flow into the space by the gap blocking wall, suppress the spread of fire, and improve the safety.

Furthermore, in a battery pack according to another embodiment of the present invention, the gap closing wall is interposed between adjacent battery cells connected by the lead plate.

Furthermore, in a battery pack according to another embodiment of the present invention, the gap closing wall is in contact with the cell covering portion via the lead plate. With the above configuration, while the battery cells are electrically connected to each other by the lead plates, even if the high-temperature gas is discharged from one battery cell, it flows into the other battery cell by arranging the gap blocking wall. situation can be contained.

Furthermore, in a battery pack according to another embodiment of the present invention, the lead plate forms a slit, and the gap blocking wall is arranged in the slit. By arranging the gap closing wall so as to pass through between the slits, the gap closing wall can be brought into direct contact with the cell covering portion without intervening the lead plate.

Furthermore, in a battery pack according to another embodiment of the present invention, the lead plate is formed in a rectangular outer shape.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. However, the embodiment shown below exemplifies a battery pack for embodying the technical idea of the present invention, and the present invention does not specify the battery pack as follows. In addition, this specification does not in any way specify the members shown in the claims as the members of the embodiment. In particular, the dimensions, materials, shapes, relative arrangements, etc. of the components described in the embodiments are not intended to limit the scope of the present invention, but are merely illustrative examples, unless otherwise specified. It's nothing more than Note that the sizes and positional relationships of members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same names and symbols indicate the same or homogeneous members, and detailed description thereof will be omitted as appropriate. Furthermore, each of the elements constituting the present invention may be configured with the same member so that a single member may serve as a plurality of elements, or conversely, the function of one member may be performed by a plurality of members. It can also be realized by sharing.

The battery pack of the present invention is mainly used as a power source for power. This battery pack is used, for example, as a power source for electric devices driven by motors, such as electric cleaners, electric tools, electric assist bicycles, electric motorcycles, electric wheelchairs, electric tricycles, and electric carts. However, the present invention does not specify the application of the battery pack. It can also be used as an auxiliary power supply.
[Embodiment 1]

A battery pack according to Embodiment 1 of the present invention is shown in FIGS. 1 to 6. FIG. 1 is a perspective view of the battery pack according to Embodiment 1, FIG. 2 is a side view of the battery pack of FIG. 1, FIG. 3 is a front view of the battery pack of FIG. 5 is an exploded perspective view of the battery pack of FIG. 1, and FIG. 6 is a further exploded perspective view of the battery pack of FIG. 5, respectively. A battery pack 100 shown in these figures includes a plurality of battery cells 1 and a battery holder 2 . The plurality of battery cells 1 are provided with electrode terminals 13 on end faces extending in the first longitudinal direction. The battery holder 2 holds the plurality of battery cells 1 parallel to each other in the first longitudinal direction, and holds the electrode terminals 13 provided at both ends of each battery cell 1 in the same plane. Each member will be described in detail below with reference to the drawings.
(Battery cell 1)

As shown in FIG. 6 , the battery cell 1 has an electrode body housed in a cylindrical outer can 11 with a bottom, and is filled with an electrolytic solution and the opening of the outer can 11 is closed with a sealing plate 3 . In the battery cell 1 , positive and negative electrode terminals 13 are formed from the bottom surface of the outer can 11 , which is both end surfaces, and the convex electrode provided at the center of the sealing plate 3 . The battery cell 1 is a rechargeable lithium ion secondary battery. However, the battery cell is not limited to a lithium ion secondary battery, and may be a chargeable/dischargeable battery such as a nickel hydrogen battery or a nickel cadmium battery. Furthermore, in the battery pack of the present embodiment, a cylindrical battery having a cylindrical outer shape is used, but it is not limited to this, and a prismatic battery or a flat battery having a rectangular outer shape can also be used. .
(Battery holder 2)

The battery holder 2 holds a plurality of battery cells 1 held in a parallel posture such that the electrode terminals 13 are arranged in a matrix. The battery holder 2 has both side end faces in the first longitudinal direction of a rectangular shape corresponding to this matrix, and the corners of the rectangular shape are chamfered along the cylindrical end faces of the battery cells 1 . Furthermore, the battery holder 2 has a rectangular shape in which the rectangular shapes on both side end surfaces in the first longitudinal direction are extended in a second longitudinal direction that intersects with the first longitudinal direction.

The battery holder 2 shown in FIGS. 1 to 6 holds a plurality of battery cells 1 parallel to each other, and holds the electrode terminals 13 provided at both ends of each battery cell 1 in a fixed position in the same plane. do. The battery holder 2 has an intermediate holding portion 8 that holds the middle portion of the battery cell 1 and an end portion holding portion 6 that holds the end portion of the battery cell 1 along the outer peripheral surface of the outer can 11 . The intermediate holding portion 8 forms a plurality of insertion cylinders into which the battery cells 1 are inserted. Here, the upper and lower portions of the intermediate holding portion 8 are sandwiched between the end portion holding portions 6, respectively. However, the present invention is not limited to this configuration. For example, the lower end holding portion may be integrated with the intermediate holding portion so that only the upper surface of the intermediate holding portion is covered with the end holding portion.

Further, the end face side of the battery cell 1 held by the end holding portion 6 is covered with the cell covering portion 7 . Particularly in the example of FIG. 6, the holder unit 2A is composed of the end holding portion 6 and the cell covering portion 7, and both ends of the plurality of battery cells 1 are held by the pair of holder units 2A. Also, the pair of holder units 2A may have the same structure and may be reversed vertically and horizontally so that a plurality of battery cells 1 can be connected in multiple series and multiple parallel.
(End holding part 6)

As shown in FIGS. 5 and 6, the end holding portion 6 includes end plate portions 21 that hold the ends of the plurality of battery cells 1, respectively. Each end plate portion 21 is positioned at both ends of the plurality of battery cells 1, and the end plate portions 21 are arranged in a posture parallel to each other. Further, the end face plate portion 21 has openings 22 through which the electrode terminals 13 are exposed. The opening 22 has a shape along the outer peripheral surface of the battery cell 1, and is preferably close to or in contact with the outer peripheral surface of the battery cell 1, and has a structure that can be connected to the outer peripheral surface of the battery cell 1 without a gap. there is This end face plate portion 21 exposes the electrode terminal 13 from the opening on the opposite side, ie, the outer side, in a state in which the end of the battery cell 1 is inserted into the opening 22 from the inner side. Further, the opening 22 has an inner shape on the side where the electrode terminals 13 are exposed, which is partially smaller than the outer shape of the outer can 11 to form a stopper portion 24 that prevents passage of the battery cell 1 . As a result, the end of the battery cell 1 inserted into the opening 22 can be stopped at a fixed position in the opening 22 without passing through the end plate portion 21 .

5 and 6, lead plates 50 connected to the electrode terminals 13 exposed from the openings 22 are arranged on the outer surface on which the end surfaces of the plurality of battery cells 1 are arranged. A concave portion 23 is formed. The end holding portion 6 shown in the drawing has a plurality of recesses 23 formed on the outer surface of the end face plate portion 21 and an insulating wall 25 provided at the boundary between adjacent recesses 23 . The insulating wall 25 insulates the adjacent lead plates 50 from each other, and blocks the jetting body jetted from the end face of the battery cell 1 in which an abnormality has occurred from being transmitted to the adjacent concave portion 23 . It is possible to suppress the spread of fire between the recessed portions 23 .

Furthermore, the end holding portion 6 is positioned between the plurality of openings 22 opened in the recess 23, that is, positioned between the battery cells 1 connected by the lead plates 50 arranged in the recess 23. , a partition wall 26 protruding from the bottom surface of the recess 23 . The end holding portion 6 shown in FIG. 5 intersects in a cross shape with the central portion of the recesses 23 in which the end faces of the four battery cells 1 are arranged among the three recesses 23 formed in the end face plate portion 21. A partition wall 26 having an intersection 27 is formed, and a linear partition wall 26 is formed in the central portion of the recess 23 where the end faces of the two battery cells 1 are arranged. The height of the partition wall 26 is formed lower than the depth of the recess 23 . These partition walls 26 can block the propagation of the ejected body ejected from the end face of the battery cell 1 in which an abnormality has occurred to the end face of the adjacent battery cell 1, thereby suppressing the spread of fire between the adjacent battery cells 1.

5 and 6, end faces of two or four battery cells 1 are arranged in one opening 22, but the end holding part 6 has one opening 22 is not specified. The end holding part 6 can change the number of battery cells 1 arranged in one opening 22 according to the number of battery cells 1 to be held and the connection state thereof. It is also possible to arrange the end faces of the battery cells. In such an opening, partition walls with a plurality of intersections can be formed to partition the opening into six regions.
(Cell covering portion 7)

The cell covering portion 7 covers the end faces of the plurality of battery cells 1 held by the end holding portion 6 . The cell covering portion 7 has a covering region 32 facing the end surface of each battery cell 1 . The cell covering portion 7 shown in FIG. 5 includes a closing plate 31 laminated and fixed to the end face plate portion 21 . The closing plate 31 has a covering region 32 facing the end face of each battery cell 1 at the center. Further, the closing plate 31 is provided with a formation recess 35 on the surface side of the covering area 32 , and the surface of the closing plate 31 that is one step lower than the surface of the closing plate 31 serves as the covering area 32 . This structure can easily adjust the thickness of the covering region 32 by adjusting the depth of the forming recess 35 . In this example, the closing plate 31 has an outer shape substantially equal to the outer shape of the end plate portion 21 , and the outer peripheral portion thereof is fixed to the end plate portion 21 . Further, the closing plate 31 is fixed to the end face plate portion 21 via a plurality of setscrews 39 passing through the outer peripheral portion. With this structure, the closing plate 31 can be firmly fixed to the end plate portion 21 , so that the closing plate 31 can be fixed to the end plate portion 21 by wind pressure or the like when a large amount of gas is instantaneously injected from the battery cell 1 due to an abnormality in the battery cell 1 . Peeling off from the portion 21 can be effectively prevented. However, the closing plate 31 can also be fixed to the end face plate portion 21 by a locking structure, adhesion, or a combination thereof.

As shown in FIG. 6 , the closing plate 31 may have a fitting projection 33 that fits into the recess 23 on the surface facing the end holding portion 6 . The fitting convex portion 33 has an outer shape substantially equal to the inner shape of the concave portion 23 formed in the end face plate portion 21 . The convex portion 33 is fitted into the concave portion 23 so that the closing plate 31 and the end holding portion 6 can be connected without a gap. This structure can prevent the ejected body ejected from the end face of the abnormal battery cell 1 from leaking outside from the boundary between the end holding portion 6 and the cell covering portion 7 .

Furthermore, the closing plate 31 shown in FIG. 6 is provided with a ring-shaped projection 34 on the surface of the fitting projection 33 at a position facing the end surface of the battery cell 1 . The ring-shaped ridge 34 is circular and has an outer shape that follows the inner shape of the stopper portion 24 provided in the opening 22 of the end face plate portion 21 . The closing plate 31 connects the ring-shaped ridge 34 to the inner surface of the stopper portion 24 without a gap, thereby suppressing the leakage of the ejection body ejected from the end surface of the battery cell 1 from this portion to the outside.

In the battery holder 2 described above, the lead plate 50 is connected to the electrode terminal 13 of the battery cell 1 exposed from the opening 22 in the concave portion 23 of the end plate portion 21 , and the closing plate 31 is attached to the outer surface of the end plate portion 21 . are stacked and fixed. In this state, the lead plate 50 is sandwiched between the end face plate portion 21 and the closing plate 31 and sealed to the battery holder 2 .

The battery holder 2 is molded from a resin such as a thermoplastic resin, which is an insulating material. The battery holder 2 may be made of a thermosetting resin, which is an insulating material, and preferably made of a resin having excellent flame resistance. For example, PC (polycarbonate) or PP (polypropylene) can be used as such a resin. In the battery holder 2, the end holding portion 6 and the intermediate holding portion 8 are molded with the same resin. Also, the cell covering portion 7 may be formed of the same resin. Also, the cell covering portion 7 may be part of the battery holder 2 . In the battery holder 2 made of resin, the intermediate holding portion 8, the end holding portion 6, and the cell cover portion 7 can be formed as separate members, or part of these can be integrally formed. Further, when the intermediate holding portion 8 is molded as a separate member, it may be molded with urethane-based resin.

The resin-made cell covering part 7 adjusts the thickness of the covering region 32 facing the end face of the battery cell 1 to adjust the energy consumption state of the ejector ejected from the battery cell 1 . By thickening the covering region 32 , the cell covering portion 7 can effectively prevent the spread of fire due to flames from reaching the battery holder 2 . In addition, by making the covering region 32 thin, the cell covering portion 7 is easily deteriorated by the energy of the flame and can suppress the spread of fire to the adjacent battery cells 1 . Accordingly, the cell covering portion 7 is designed to have an optimum thickness in consideration of these factors. The cell covering portion 7 is designed to have an optimum thickness depending on, for example, the type and capacity of the battery cell 1 used, the material of the resin used for the cell covering portion 7, and the like. For the cell covering portion 7, for example, when a lithium ion secondary battery having a capacity of 4 Ah is used as the battery cell 1, and the cell covering portion 7 is formed of polycarbonate, the thickness of the covering region 32 is set to 0.5 to 3.0 mm. As 0 mm, the energy of the ejector can be efficiently reduced.

However, in the battery holder, the end holding portion may be made of resin and the cell covering portion may be made of metal. The metal cell covering portion can be a metal plate with a predetermined thickness. Iron, aluminum, copper, or the like can be used as such a metal plate. The cell covering portion made of a metal plate can be insulated by applying an insulating paint on the surface. The cell covering portion made of the metal plate is also made to have a thickness such that it can be melted or deformed by the energy of the ejection body ejected from the battery cell.

In the battery holder 2 described above, the ends of the battery cells 1 are held by the end holding portions 6 of each holder unit 2A, that is, the ends of the battery cells 1 are held in the openings 22 provided in the end plate portions 21 facing each other. The battery cell 1 is held at a fixed position by connecting the pair of holder units 2A in a state where the battery cell 1 is inserted. The pair of holder units 2A is connected to a second boss 29 provided at the end of the other end plate portion 21 while a connecting screw 38 is inserted through the first boss 28 provided at the end of one end plate portion 21. By screwing the screws 38, they are connected and fixed. However, the pair of holder units can also be connected by a locking structure, by bonding, or by combining them.

The end holding portion 6 of the battery holder 2 described above has a plurality of openings 22 formed in the end face plate portion 21 in order to insert and hold the ends of the battery cells 1 . In this battery holder 2, a pair of holder units 2A holds both end portions of a plurality of battery cells 1 and arranges them in fixed positions. This battery holder 2 holds the middle portion of each battery cell 1 in a fixed position in a state where it is exposed without being covered. This battery holder 2 can be made lightweight with a simple structure.
(Lead plate 50)

The lead plate 50 is arranged in the concave portion 23 formed in the end holding portion 6 and connected to the electrode terminals 13 of the plurality of battery cells 1 . The lead plate 50 is welded and connected to the electrode terminal 13 of the battery cell 1 by a method such as spot welding or laser welding. A material having good electrical and thermal conductivity is used for the lead plate 50, and a metal plate such as an iron plate, a nickel plate, a copper plate, an aluminum plate, etc. whose surface is plated with nickel or the like can be suitably used. In the battery holder 2 , three lead plates 50 are arranged on each end face plate portion 21 of each holder unit 2</b>A and connected to the electrode terminals 13 of the battery cells 1 .
(Connecting portion 52)

The lead plate 50 shown in FIGS. 5 and 6 connects a plurality of battery cells 1 arranged in multiple rows and rows in series and in parallel. In order to connect the plurality of battery cells 1 in series and in parallel, the lead plate 50 includes a plurality of connection portions 51 to be connected to the electrode terminals 13 of the battery cells 1 and a connection formed by connecting the plurality of connection portions 51 . a portion 52; The lead plate 50 is connected to a lead plate 50A that connects four battery cells 1 arranged in two rows and two rows in two series and two parallel lines, and to both ends of a plurality of battery cells 1 that are connected in series with each other. A lead plate 50B for connecting two battery cells 1 in parallel is provided.

The lead plate 50A has four connection portions 51 arranged to face the electrode terminals 13 of the four battery cells 1 arranged in two rows and two rows, and these connection portions 51 are connected to each other. They are connected by four connecting portions 52 provided between the portions 51 . In addition, the lead plate 50B has two connection portions 51 arranged to face the electrode terminals 13 of the two battery cells 1, and these connection portions 51 are provided between the adjacent connection portions 51. They are connected at a connecting portion 52 . Further, the lead plate 50B has an output lead portion 55 for output. An output lead portion 55 provided on the lead plate 50B is led out from between the end holding portion 6 and the cell covering portion 7 to the outside.
(Groove 53)

Further, the lead plate 50 has a groove portion 53 formed by bending a connecting portion 52 provided between the connecting portions 51 in order to guide the partition wall 26 formed in the recess portion 23 . The lead plate 50B has a linear groove portion 53 formed between the two connection portions 51 so that the dividing wall 26 can be guided through the groove portion 53. As shown in FIG. The lead plate 50A has four groove portions 53 formed between the four connection portions 51. These groove portions 53 are formed in directions intersecting each other in a cross shape to guide the partition wall 26 intersecting in a cross shape. I'm trying Furthermore, the lead plate 50A has a through-hole 54 at a position facing the intersection 27 of the intersecting partition wall 26 . This lead plate 50A can easily form a plurality of grooves 53 in cross-shaped crossing directions by opening through holes 54 at positions facing the intersections 27 . In the lead plate 50 described above, the grooves 53 provided between the connection portions 51 are arranged in the partition wall 26 , so that the connection portions 52 of the lead plate 50 are arranged along the partition wall 26 and the plurality of connection portions 51 are arranged. can be brought close to the electrode terminal 13 of the battery cell 1 to ensure electrical connection. Further, by guiding the groove portion 53 to the partition wall 26, the lead plate 50 can be positioned at a fixed position.

The lead plate 50A shown in FIGS. 5 and 6 connects the electrode terminals 13 of the four battery cells 1 arranged in two rows and two rows. Not limited. The lead plate can connect six battery cells arranged in three rows and two rows, or eight battery cells arranged in four rows and two rows.
(Battery Assembly 10)

The battery holder 2 shown in FIGS. 1 to 6 holds a plurality of battery cells 1 in a fixed position by the end holding portion 6, and holds the plurality of battery cells 1 arranged in the concave portion 23 provided in the end holding portion 6. The electrode terminals 13 are connected by the lead plates 50 , the closing plate 31 is fixed to the surface of the end holding portion 6 , and the end surface side of the battery cell 1 is covered with the cell covering portion 7 to form the battery assembly 10 .

In the battery assembly 10 shown in FIGS. 5 and 6, a plurality of battery cells 1 are arranged in parallel, arranged in multiple rows and columns, and arranged in a fixed position with a battery holder 2 . In the battery pack 100 of this embodiment, ten battery cells 1 are arranged in two rows and five columns, and these battery cells 1 are electrically connected in five series and two parallel. However, the present invention does not specify the number of battery cells 1 to be housed or the structure of arranging them in multiple rows and columns.

Note that the battery pack 100 shown in FIGS. 1 to 6 does not have a double structure of a battery holder and an exterior case as in the conventional case, but uses the battery holder itself as an exterior case. As a result, further miniaturization and weight reduction and cost reduction can be achieved. However, the purpose of the present invention is to avoid the unintended spread of fire in battery cells. It goes without saying that it is possible to
(exhaust hole)

The battery cell 1 has an exhaust hole provided in the sealing plate 3 provided with the convex electrode, and a safety valve provided in this exhaust hole. Even if the internal pressure of the battery cell rises abnormally due to overcharging, an internal short circuit, or the like, the battery cell 1 opens the safety valve and exhausts the internal gas through the exhaust hole, thereby ensuring safety. increasing. Such a safety valve is generally provided on the positive electrode side of the battery cell.

On the other hand, if an ejector such as a high-pressure gas or flame is emitted from one of the battery cells, there is concern that the high temperature of the ejector may adversely affect the other battery cells. The ejection time of the ejector is relatively short, and the pressure and temperature of the ejected ejector are reduced in inverse proportion to the square of the distance, but the distance between adjacent battery cells 1 is relatively short. Therefore, there is a concern that the inflow of the jetting body will expose it to high temperature and high pressure. Especially in the case of a cylindrical battery cell, since the sealing plate 3 is crimped and fixed to the opening of the outer can 11 via an insulating resin, the insulating resin, which is the joint portion of the crimp, is rapidly heated. It is feared that it will adversely affect
(Exhaust port 60)

Therefore, in this embodiment, the outlet 60 is formed in the side surface of the battery holder 2 along the first longitudinal direction. The outlet 60 allows the electrode terminals 13 of the battery cells 1 accommodated inside the battery holder 2 to communicate with the outside of the battery holder 2 . With this configuration, even in the unlikely event that any of the battery cells 1 emits a jet, it will be discharged from the discharge port 60 opened in the side surface of the battery holder 2 as indicated by the arrows in FIGS. 1 to 6 . The ejection body can be discharged to the outside of the battery pack. As a result, it is possible to avoid exposing the adjacent battery cells 1 to the high temperature and high pressure of the ejector, thereby improving safety. It is preferable that the end of the discharge port 60 is communicated with a discharge path through which the device to be driven in which the battery pack 100 is provided can safely discharge the battery pack 100 to the outside. For example, the exhaust port 60 is communicated with the exhaust duct of the device to be driven.

It is preferable to provide a plurality of outlets 60 . In the example of FIG. 1 and the like, the outlet 60 includes a corner outlet 61 and an intermediate outlet 62 . The corner outlet 61 is opened in a curved shape at the chamfered corner portion of the side surface of the battery holder 2 . By continuously opening the corner outlet 61 at the chamfered corner portion of the outlet 60 in this way, compared to the case where the outlet 60 is opened in a slit shape at the rectangular corner of the battery holder 2, the rectangular shape is reduced. It is possible to avoid a situation in which high-pressure ejection bodies accumulate at the corners of the shape, and it is possible to smoothly discharge the ejection bodies from the battery cell 1 to the outside with less resistance. In particular, when thermal runaway occurs, it is necessary to discharge high-pressure gas to the outside of the battery holder 2 in a short period of time, and pressure tends to concentrate at the corners of the rectangular shape, which may cause gas pools. Therefore, by chamfering and eliminating such corners where pressure is likely to be concentrated, and by forming the discharge port 60 in a slit-like manner continuously from the corners, the high-pressure ejection body can be quickly discharged from the outside. can be guided to discharge to

The intermediate discharge port 62 is opened in the middle of the second longitudinal direction on the side surface of the battery holder 2 . By opening the intermediate discharge port 62 between the corner discharge ports 61 in this way, it is possible to further improve the discharging performance of the ejector.

Further, the outlet 60 is preferably opened on the side of the electrode terminals 13 of the plurality of battery cells 1 facing the positive electrodes. As described above, a battery cell generally has a safety valve on the positive electrode terminal. Therefore, if an ejection body containing high-temperature, high-pressure gas is released, it is highly likely that it will occur on the positive electrode side. Therefore, by opening the discharge port 60 so that each positive electrode terminal communicates with the outside of the battery pack, it is possible to efficiently discharge the ejection body to the outside, thereby avoiding a situation in which the adjacent battery cells are adversely affected. .

The position of the electrode terminal 13 on the positive electrode side in the battery pack changes depending on the form and the number of serial or parallel connection of the plurality of battery cells 1 . Therefore, the opening position of the discharge port 60 is set according to such a connection form and the number. Preferably, the connection form is such that the positive terminals are dispersed so as not to concentrate the positive terminals as much as possible. In the example of FIG. 5, 10 battery cells are connected in 5 series and 2 rows. With this connection configuration, the positive terminals of the two battery cells are arranged alternately with the negative terminal interposed therebetween, so the number of adjacent positive terminals can be reduced to only two, which is excellent in terms of safety. . Furthermore, by opening the outlet 60 in each positive electrode terminal, the outlet 60 itself can be made smaller, and the decrease in strength of the battery holder 2 due to the opening of the outlet 60 can be suppressed.
[Embodiment 2]

Further, in the above configuration, an example in which the corner discharge port 61 is continuously provided in the corner portion has been described. However, the present invention is not limited to this configuration, and the discharge port 60 may be provided discontinuously at the corner portion. Such a configuration is shown in the perspective view of FIG. 7 as a battery pack 200 according to the second embodiment. In the battery pack 200 shown in this figure, a support 63 is provided in the middle of the corner outlet 61 to divide the corner outlet 61 into two divided corner outlets 61a and 61b. With this configuration, the corners of the battery pack 200, which require strength against impact such as dropping, are reinforced to suppress the decrease in strength due to the opening of the discharge port 60. Even if the ejection body is ejected from 1, the other battery cells 1 inside the battery pack 200 can be protected by ejecting it from the outlet 60 to the outside of the battery pack.
[Embodiment 3]

Further, in order to reduce the influence of the ejector on adjacent battery cells, a gap blocking wall may be formed between the adjacent battery cells. Such an example is shown in the exploded perspective view of FIG. 8 as a battery pack 300 according to the third embodiment. In the battery pack 300 shown in this figure, the same reference numerals are assigned to the same members as in the first embodiment and the like, and detailed description thereof will be omitted as appropriate. In the battery pack 300 shown in this figure, the end holding portion 6 of the battery holder 2 forms a gap closing wall 26A projecting so as to come into contact with the cell covering portion 7 on the surface facing the cell covering portion 7 . ing. By providing the gap blocking wall 26A between the adjacent battery cells 1 in this manner, even if the high-temperature ejecting body is discharged from one battery cell, the ejecting body flows out to the other battery cell. The gap blocking wall 26A can prevent such a situation. The gap closing wall 26A is interposed between the adjacent battery cells 1 connected by the lead plate 50. As shown in FIG. Also, the gap closing wall 26A protrudes from the upper surface of the partition wall 26. As shown in FIG. Therefore, the upper surface of the partition wall 26 is not flush, and only the upper surface of the partition wall 26 provided with the gap block wall 26A is raised. It should be noted that the gap blocking wall 26A does not need to be in complete contact with the cell covering portion 7, and it is sufficient if it is held to the extent that it can block the ejector. That is, it is not required to be airtightly closed.

In addition, as described above, the battery cell 1 has a safety valve on the positive electrode side, and it is on the positive electrode side that the ejector may be discharged. Therefore, the gap blocking wall 26A is arranged so as to be interposed between the battery cells 1 at the portion where the positive electrode side of the battery cell is adjacent to another battery cell. In this way, by providing the gap blocking wall 26A on the positive electrode side where the safety valve is provided, even if the safety valve is opened, the high-temperature ejected body discharged from the safety valve will flow into the adjacent battery cell. It can be suppressed at 26A, and safety is enhanced.
[Embodiment 4]

In the above example, the configuration in which the gap closing wall contacts the cell covering portion 7 via the lead plate has been described. However, the present invention is not limited to this configuration, and a configuration in which the gap closing wall directly abuts the cell covering portion without interposing a lead plate may be employed. Such a configuration is shown in the exploded perspective view of FIG. 9 as a battery pack 400 according to the fourth embodiment. In this figure as well, members similar to those of the first to third embodiments described above are denoted by the same reference numerals, and detailed description thereof will be omitted as appropriate.

Battery pack 400 shown in FIG. 9 has slits 56 formed in lead plate 50 . The lead plate 50 is fixed to the battery cell 1 in such a posture that the slit 56 is disposed on the gap blocking wall 26A. By disposing the gap blocking wall 26A between the slits 56 in this manner, the gap blocking wall 26A can be brought into direct contact with the cell covering portion 7 without interposing the lead plate 50 therebetween. The connecting portion 51 of the lead plate 50 is not electrically connected at the portion where the slit 56 is provided, but by connecting the upper surface of the partition wall 26 where the gap blocking wall 26A is not provided with the connecting portion 52, the four connecting portions can be connected. 51 is electrically connected and the four battery cells 1 are maintained at the same potential.

In Examples 3 and 4 described above, the gap block wall 26A is provided between the adjacent battery cells 1, so that even if high-temperature gas is discharged from one battery cell, The risk of fire spreading can be reduced by preventing the flow of heat into the end face side of the other battery cell.

The battery pack according to the present invention is a battery pack that enhances safety by suppressing the spread and spread of fire caused by ejection bodies ejected from the end surfaces of battery cells when there is an abnormality in the battery cells. It can be suitably used as a power source for electric tricycles, electric carts, cleaners, electric blowers, etc., and for power storage in homes and shops.

DESCRIPTION OF SYMBOLS 100, 200, 300, 400... Battery pack 1... Battery cell 2... Battery holder 2A... Holder unit 3... Sealing plate 6... End holding part 7... Cell covering part 8... Intermediate holding part 10... Battery assembly 11... Outer can REFERENCE SIGNS LIST 13: Electrode terminal 21: End plate portion 22: Insertion hole 23: Recess 24: Stopper portion 25: Insulating wall 26: Partition wall 26A: Gap closing wall 27: Crossing portion 28: First boss 29: Second boss 31: Closed Plate 32 Covered area 33 Fitting projection 34 Protrusion 35 Forming recess 38 Connecting screw 39 Set screw 50, 50A, 50B Lead plate 51 Connecting portion 52 Connecting portion; 52A High connecting portion; 52B... Low connecting part 53... Groove part 54... Through hole 55... Output lead part 56... Slit 60... Discharge port 61... Corner discharge port 61a, 61b... Divided corner discharge port 62... Intermediate discharge port 63... Support

Claims (9)

a plurality of battery cells having electrode terminals provided on end faces extending in the first longitudinal direction and having a safety valve provided on at least one end face ;
a battery holder that holds the plurality of battery cells in a posture parallel to each other in the first longitudinal direction and in a posture in which electrode terminals provided at both ends of each battery cell are arranged in the same plane;
A battery pack comprising
The battery holder is
an edge holder that holds an edge having one or more safety valves of the plurality of battery cells;
a cell covering portion laminated and fixed to the end holding portion and covering an end face side of the battery cell held by the end holding portion;
with
The end holding portion has a plurality of recesses in which lead plates connecting electrode terminals of adjacent battery cells are arranged, respectively, and an insulating wall for insulating the lead plates at the boundary between the adjacent recesses. have
A battery pack in which the battery holder has a side surface along the first longitudinal direction formed with an outlet for communicating the plurality of concave portions in the end holding portion with the outside of the battery holder. A battery pack according to claim 1,
The plurality of battery cells have a cylindrical outer shape,
The battery holder holds the plurality of battery cells held in a parallel posture so that the respective electrode terminals are arranged in a matrix,
Both end faces in the first longitudinal direction are rectangular according to the matrix, and corners of the rectangular shape are chamfered along the cylindrical end faces of the battery cells,
The battery pack, wherein the outlet includes a corner outlet opening in a curved shape at a chamfered corner portion of the side surface of the battery holder. The battery pack according to claim 2,
The battery holder has a rectangular shape in which the rectangular shapes on both side end faces in the first longitudinal direction are extended in a second longitudinal direction that intersects with the first longitudinal direction,
The battery pack, wherein the outlet includes an intermediate outlet opened in the middle of the second longitudinal direction on the side surface of the battery holder. The battery pack according to any one of claims 1 to 3,
Each of the plurality of battery cells is provided with the safety valve on the positive electrode side of the electrode terminal,
The battery holder is a battery pack in which the discharge port is opened on the positive electrode side of the electrode terminals of the plurality of battery cells. The battery pack according to claim 4,
The battery holder is a battery pack in which the discharge port is opened for each positive electrode of the electrode terminals of the plurality of battery cells. The battery pack according to any one of claims 1 to 5 ,
A battery pack in which the battery holder has a gap closing wall projecting so as to abut against the cell covering portion on a surface facing the cell covering portion. A battery pack according to claim 6,
A battery pack in which the gap closing wall is interposed between adjacent battery cells connected by the lead plate. The battery pack according to claim 6 or 7,
A battery pack in which the gap closing wall is in contact with the cell covering portion via the lead plate. The battery pack according to claim 6 or 7,
The lead plate forms a slit,
A battery pack in which the gap blocking wall is arranged in the slit.

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