JP7346057B2 - battery pack - Google Patents

Description

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

In recent years, demand for reusable secondary batteries such as nickel metal hydride, nickel cadmium, and lithium ion has been increasing from the perspective of resource and energy conservation. Among them, lithium ion secondary batteries have the characteristics of being lightweight, high electromotive force, and high energy density. For this reason, the demand for power supplies for driving various types of portable electronic devices and mobile communication devices, such as mobile phones, digital cameras, video cameras, and notebook computers, is increasing.

On the other hand, as devices become smaller and their energy density increases, there is a risk that they may generate heat to high temperatures depending on how they are used. For this reason, safety in batteries and battery packs has become more important.

For example, when a battery as described above is overcharged, overdischarged, or shorted internally or externally, gas may be generated internally. The gas thus generated increases the internal pressure of the battery. If such a situation occurred, there was a possibility that the outer can would burst due to the increase in internal pressure. In order to prevent such explosions, these batteries are provided with exhaust holes and safety valves for venting gas.

Furthermore, in order to improve the safety of battery packs in which such batteries are housed within a housing, a structure has been proposed in which this gas is released to the outside of the housing. Furthermore, in a state where such gas is generated, there is a risk that smoke or ignition may occur within the battery pack due to the influence of an overheated battery, for example.

BACKGROUND ART A battery pack has been proposed that effectively prevents multiple batteries from catching fire while suppressing the influence of ejected bodies such as high-temperature gas and flames ejected from the batteries on the outside of the battery pack (for example, Patent Document 1). As shown in FIG. 9, this battery pack includes a plurality of battery cells 1 formed by closing the opening of a cylindrical outer can 11 with a bottom with a sealing plate, and a plurality of battery cells 1 arranged in parallel to each other. , and a battery holder 2 that holds the electrode terminals provided at both ends of each battery cell 1 in a position where they are arranged on the same surface, and an exterior housing that houses a battery assembly 10 formed by holding a plurality of battery cells 1 with the battery holder 2. Case 4 is included. The battery holder 2 includes a holding part 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 part that covers the end surface side of the plurality of battery cells 1 held by the holding part 6. 7, and is configured so that when the battery cell 1 is abnormal, the covering portion 7 is altered by the energy of the ejected body ejected from the end face of the battery cell 1.

Re-publication No. 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 whose electrode surface is on the same plane as that battery cell. As a result, there was a possibility that it would get heated and cause a fire.

One object of the present invention is to provide a battery pack that can suppress the adverse effects on other battery cells due to ejected objects such as high-temperature gas ejected from a battery cell or flames upon ignition.

A battery pack according to one embodiment of the present invention includes a plurality of battery cells each having a positive electrode terminal and a negative electrode terminal on an end face extending in the longitudinal direction, and a plurality of battery cells arranged in parallel to each other in the longitudinal direction. , and a battery holder that holds electrode terminals provided at both ends of each battery cell in an attitude in which they are arranged on the same plane, a lead plate that connects electrode terminals of adjacent battery cells, and the lead of the battery holder. and a cell covering portion that covers the surface on which the plate is provided. The battery holder has a gap closing wall that protrudes so as to come into contact with the cell covering part on a surface facing the cell covering part, and the battery holder has a gap closing wall that protrudes so as to come into contact with the cell covering part, and the battery holder has a gap closing wall that protrudes so as to come into contact with the cell covering part. It has an opening for opening a portion facing the lead plate, and a lattice-like intersection is provided in the opening, and the upper surface of the intersection is partially protruded to form the gap closing wall. Each of the plurality of battery cells is provided with a safety valve on the positive electrode side, and one of the plurality of battery cells has a safety valve between the battery cells at a portion where the positive electrode side is adjacent to the other battery cell. The gap closing wall is disposed at .

According to the above battery pack, by providing a gap closing wall between adjacent battery cells, even if high-temperature gas is discharged from one battery cell, this gas will be transferred to the other adjacent battery. The gap closing wall prevents the fuel from flowing into the end face side of the cell, thereby suppressing the risk of concomitant fire and increasing safety.

1 is a perspective view showing a battery pack according to Embodiment 1. FIG. FIG. 2 is an exploded perspective view of the battery pack of FIG. 1. FIG. 3 is a further exploded perspective view of the battery pack of FIG. 2. FIG. FIG. 2 is a vertical cross-sectional view of the battery pack of FIG. 1 taken along line IV-IV. FIG. 5 is an enlarged view of main parts of the battery pack of FIG. 4. FIG. FIG. 2 is an enlarged view of main parts of a battery pack according to a comparative example. FIG. 2 is an exploded perspective view of a battery pack according to a second embodiment. FIG. 8 is an enlarged vertical sectional view of a main part of the battery pack of FIG. 7; FIG. 2 is an exploded perspective view showing a conventional battery pack.

In addition to the above-described configuration, a battery pack according to an embodiment of the present invention may have the following configuration.

In the battery pack according to one embodiment of the present invention, the gap closing wall is interposed between adjacent battery cells connected by the lead plate.

Moreover, in the 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, battery cells are electrically connected to each other by lead plates, and a gap closing wall is placed, so that even if high-temperature gas is discharged from one battery cell, it will flow into the other battery cell. We can control the situation.

Furthermore, in a battery pack according to another embodiment of the present invention, the lead plate has a slit. The gap closing wall is arranged in the slit. With the above configuration, by arranging the gap closing wall so as to pass between the slits, it is possible to directly bring the gap closing wall into contact with the cell covering portion without intervening a lead plate.

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

Furthermore, according to a battery pack according to another embodiment of the present invention, each of the plurality of battery cells is provided with a safety valve on the positive electrode side. The gap closing wall is disposed between the battery cells at a portion where one of the plurality of battery cells is adjacent to another battery cell on its positive electrode side. With the above configuration, by providing a gap closing wall between the positive electrode side where the safety valve is provided and other battery cells, even if the safety valve is opened, the high temperature gas discharged from the safety valve will be transferred to the adjacent battery cells. This situation can be suppressed by the gap closing wall, increasing safety.

Furthermore, according to the battery pack according to another embodiment of the present invention, the gap closing wall is arranged between the plurality of battery cells in a region where the positive electrodes are adjacent to each other. There is. With the above configuration, by providing a gap closing wall between battery cells where positive electrodes with safety valves are adjacent to each other, even if one of the safety valves is opened, the high temperature gas discharged from the safety valve will be adjacent to the other battery cells. It is possible to avoid the situation where the liquid flows into the battery cells and heats the joints of the sealing plates, improving safety.

Furthermore, according to the battery pack according to another embodiment of the present invention, the battery holder has an opening at a portion where the battery cell held by the battery holder faces the lead plate, and the opening has a lattice pattern. A partition wall has been installed. The upper surface of the partition wall is partially protruded to form the gap closing wall. With the above configuration, the opening of the battery holder is reinforced by the partition wall, and the top surface of the partition wall is partially protruded to form a gap closing wall, which can also be used as a structure for safety measures in the event of thermal runaway. This has the advantage of simplifying the configuration.

Furthermore, according to the battery pack according to another embodiment of the present invention, the battery holder includes an intermediate holding portion that holds an intermediate portion of the plurality of battery cells, and an end that holds an end portion of the plurality of battery cells. and a holding section.

Furthermore, according to a battery pack according to another embodiment of the present invention, the plurality of battery cells have a cylindrical outer shape.

Embodiments of the present invention will be described below based on the drawings. However, the embodiments shown below illustrate battery packs for embodying the technical idea of the present invention, and the present invention does not specify the battery packs as described below. Moreover, this specification does not in any way specify the members shown in the claims to the members of the embodiments. 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, unless otherwise specified, and are merely illustrative examples. It's nothing more than that. Note that the sizes, positional relationships, etc. 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 descriptions will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured so that a plurality of elements are made of the same member so that one member serves as a plurality of elements, or conversely, the function of one member may be performed by a plurality of members. It can also be accomplished by sharing.

The battery pack of the present invention is mainly used as a power source for motive power. This battery pack is used 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 use of the battery pack, and is intended to be applied to electric devices other than electric devices, such as power sources for various electric devices used indoors and outdoors such as radios and lighting devices, power sources for transportation means, and It can also be used as an auxiliary power source.
[Embodiment 1]

A battery pack according to Embodiment 1 of the present invention is shown in FIGS. 1 to 5. In these figures, FIG. 1 is a perspective view of the battery pack 100 according to the first embodiment, FIG. 2 is an exploded perspective view of the battery pack 100 of FIG. 1, and FIG. 3 is a further exploded perspective view of the battery pack 100 of FIG. , FIG. 4 shows a vertical cross-sectional view of the battery pack 100 in FIG. 1 taken along the line IV--IV, and FIG. 5 shows an enlarged view of the main parts of the battery pack 100 in FIG. 4. A battery pack 100 shown in these figures includes a plurality of battery cells 1, a battery holder 2, a lead plate 50, and a cell covering part 7. Each of the plurality of battery cells 1 is provided with a positive electrode terminal 13 and a negative electrode terminal 13 on an end face extending in the longitudinal direction. The battery holder 2 holds a plurality of battery cells 1 in a posture parallel to each other in the longitudinal direction, and in a posture in which electrode terminals 13 provided at both ends of each battery cell 1 are arranged on the same plane. The lead plate 50 connects the electrode terminals 13 of adjacent battery cells 1 to each other. The cell covering portion 7 covers the surface of the battery holder 2 on which the lead plate 50 is provided.
(Battery cell 1)

In the battery cell 1, an electrode body is housed in a cylindrical outer can 11 with a bottom, an electrolyte is filled, and an opening of the outer can 11 is closed with a sealing plate 3. In the battery cell 1, the bottom surface of the outer can 11, which is both end surfaces, and a convex electrode provided at the center of the sealing plate 3 serve as positive and negative electrode terminals 13. The battery cell 1 is a lithium ion secondary battery that can be charged and discharged. 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. Further, in the battery pack of this example, a cylindrical battery with a cylindrical outer shape is used, but the present invention is not limited to this, and a square battery or a flat battery with a rectangular outer shape may also be used. .
(Battery holder 2)

The battery holder 2 shown in FIGS. 2 to 5 holds a plurality of battery cells 1 in a fixed position in a posture parallel to each other and with electrode terminals 13 provided at both ends of each battery cell 1 arranged on the same surface. do. The battery holder 2 shown in FIG. 3 has an intermediate holding part 8 that holds the middle of the battery cell 1, and an end holding part 6 that holds the end 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 tubes into which the battery cells 1 are inserted. Here, the upper and lower ends of the intermediate holding part 8 are sandwiched between the end holding parts 6, respectively. However, the present invention is not limited to this configuration. For example, the lower end holding part may be integrated with the intermediate holding part, and only the upper surface of the intermediate holding part may be covered with the end holding part.

Further, the end face side of the battery cell 1 held by the end holding part 6 is covered with a cell covering part 7. In particular, in the example shown in FIG. 3, the end holding portion 6 and the cell covering portion 7 constitute a holder unit 2A, and both ends of the plurality of battery cells 1 are held by the pair of holder units 2A. Furthermore, the pair of holder units 2A may have the same structure but be reversed vertically and horizontally, so that a plurality of battery cells 1 can be connected in multiple series and multiple parallel configurations.
(End holding part 6)

As shown in FIGS. 2 to 5, 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 located at both ends of the plurality of battery cells 1, and the end plate portions 21 are arranged in parallel to each other. Further, the end plate portion 21 has an opening 22 through which the electrode terminal 13 is exposed, as shown in FIG. This opening 22 has a shape that follows the outer circumferential surface of the battery cell 1, and preferably has a structure in which it approaches or contacts the outer circumferential surface of the battery cell 1 and can be connected to the outer circumferential surface of the battery cell 1 without a gap. There is. This end plate portion 21 allows the electrode terminal 13 to be exposed from the opening on the outer side, which is the opposite side, while 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 partially smaller than the outer shape of the outer can 11 on the side where the electrode terminal 13 is exposed, thereby forming a stopper portion 24 that prevents the battery cell 1 from passing through. Thereby, the end of the battery cell 1 inserted into the opening 22 can be stopped at a fixed position in the opening 22 without penetrating the end plate portion 21.

Furthermore, the end holding part 6 shown in FIG. 3 has a recess 23 on the outer surface where the end surfaces of the plurality of battery cells 1 are arranged, in which a lead plate 50 connected to the electrode terminal 13 exposed from the opening 22 is arranged. is formed. The end holding portion 6 shown in the figure has a plurality of recesses 23 formed on the outer surface of the end plate portion 21, and an insulating wall 25 is provided at the boundary between adjacent recesses 23. This insulating wall 25 insulates the lead plates 50 that are arranged adjacent to each other, and also blocks the ejected body ejected from the end face of the battery cell 1 where an abnormality has occurred from being transmitted to the adjacent recess 23. It is possible to suppress the spread of fire between the concave portions 23.

Furthermore, the end holding portion 6 is located between the plurality of openings 22 opened in the recess 23, that is, between the battery cells 1 connected by the lead plate 50 disposed in the recess 23. , a partition wall 26 protruding from the bottom surface of the recess 23. The end holding part 6 shown in FIG. 3 intersects in a cross shape in the center of the recess 23 in which the end faces of the four battery cells 1 are arranged among the three recesses 23 formed in the end plate part 21. A partition wall 26 having an intersection 27 is formed, and a linear partition wall 26 is formed in the center of the recess 23 in which the end faces of the two battery cells 1 are arranged. The height of the partition wall 26 is formed to be lower than the depth of the recess 23. These partition walls 26 can prevent the ejected body ejected from the end face of the battery cell 1 in which the abnormality has occurred from being transmitted to the end face of the adjacent battery cell 1, thereby suppressing the spread of fire between the adjacent battery cells 1.

In the end holding part 6 shown in FIGS. 2 and 3, the end faces of two or four battery cells 1 are arranged in one opening 22. The number of battery cells 1 to be placed is not specified. The end holding portion 6 can vary the number of battery cells 1 arranged in one opening 22 depending on the number of battery cells 1 to be held and their connection state. It is also possible to arrange the end faces of the battery cells. In such an opening, a partition wall having a plurality of intersections may be formed to partition the opening into six regions.
(Cell covering part 7)

The cell covering section 7 covers the end surfaces of the plurality of battery cells 1 held by the end holding section 6 . This cell covering portion 7 has a covering region 32 facing the end face of each battery cell 1 . The cell covering section 7 shown in FIGS. 1 to 3 includes a closing plate 31 that is laminated and fixed to the end plate section 21. The closing plate 31 includes a covering region 32 in the center thereof, which faces the end surface of each battery cell 1 . Further, the closing plate 31 has a forming recess 35 on the surface side of the covering area 32, and the covering area 32 is a surface that is one step lower than the surface of the closing plate 31. With this structure, the thickness of the covering region 32 can be easily adjusted by adjusting the depth of the forming recess 35. In this example, the closure plate 31 has an outer circumferential edge portion fixed to the end plate portion 21 so as to have an outer shape substantially equal to the outer shape of the end plate portion 21 . Further, the closing plate 31 is fixed to the end plate portion 21 via a plurality of set screws 39 passing through the outer peripheral edge. With this structure, the closing plate 31 can be firmly fixed to the end plate part 21, so that the closing plate 31 can be firmly fixed to the end plate part 21 due to 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 plate portion 21 by a locking structure, adhesive, etc., or by a combination of these.

As shown in FIG. 3, the closing plate 31 may have a fitting convex portion 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 that is approximately the same as the inner shape of the recess 23 formed in the end plate portion 21, and when the end plate portion 21 is closed by the closing plate 31, the fitting convex portion 33 is inserted into the closing plate 31. 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 suppress the ejected body ejected from the end face of the battery cell 1 in which an abnormality has occurred from leaking to the outside from the boundary between the end holding part 6 and the cell covering part 7.

Furthermore, the closure plate 31 shown in FIG. 3 has a ring-shaped protrusion 34 on the surface of the fitting protrusion 33 at a position facing the end surface of the battery cell 1. The ring-shaped protrusion 34 has a circular shape, and has an outer shape that follows the inner shape of the stopper portion 24 provided in the opening 22 of the end plate portion 21. This closing plate 31 connects a ring-shaped protrusion 34 to the inner surface of the stopper portion 24 without a gap, thereby suppressing the ejected body ejected from the end face of the battery cell 1 from leaking to the outside from this portion.

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 recess 23 of the end plate 21, and the closing plate 31 is attached to the outer surface of the end plate 21. are stacked and fixed. In this state, the lead plate 50 is sandwiched between the end plate portion 21 and the closing plate 31 and sealed in the battery holder 2.

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

The cell covering portion 7 made of resin 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 ejected body ejected from the battery cell 1. The cell covering portion 7 can effectively prevent the spread of fire from reaching the battery holder 2 by making the covering region 32 thick. Further, by making the covering region 32 thin, the cell covering portion 7 can be easily altered by the energy of the flame, thereby suppressing the spread of fire to the adjacent battery cells 1. Therefore, the cell covering portion 7 is designed to have an optimal thickness in consideration of these matters. The cell covering portion 7 is designed to have an optimal 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 example, when a lithium ion secondary battery having a capacity of 4Ah is used as the battery cell 1 and the cell covering portion 7 is molded from polycarbonate, the thickness of the covering region 32 is set to 0.5 to 3.5 mAh. By setting the diameter to 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 having a predetermined thickness. Iron, aluminum, copper, etc. 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 to the surface. The cell covering portion made of a metal plate is also thick enough to be melted or deformed by the energy of the ejected body ejected from the battery cell.

The battery holder 2 described above is in a state where the ends of the battery cells 1 are held by the end holding parts 6 of each holder unit 2A, that is, both ends of the battery cells 1 are held in the openings 22 provided in the opposing end plate parts 21. A pair of holder units 2A are connected in a state where the battery cell 1 is inserted, and the battery cell 1 is held in a fixed position. The pair of holder units 2A are connected to a second boss 29 provided at the end of the other end plate 21 by inserting a connecting screw 38 into a first boss 28 provided at the end of the other end plate 21. They are connected and fixed by screwing in the screws 38. However, the pair of holder units can be connected by a locking structure, by adhesive, or by a combination of these.

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

The lead plate 50 is placed in the recess 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. The lead plate 50 is made of a material with good electrical conductivity and thermal conductivity, and metal plates such as iron plates, nickel plates, copper plates, and aluminum plates whose surfaces are plated with nickel or the like can be suitably used. In the battery holder 2, three lead plates 50 are arranged on the end plate portion 21 of each holder unit 2A, and are connected to the electrode terminals 13 of the battery cells 1.
(Connection part 52)

The lead plate 50 shown in FIGS. 2 and 3 connects a plurality of battery cells 1 arranged in multiple stages and rows in series and in parallel. This lead plate 50 is a connection formed by connecting a plurality of connection parts 51 connected to the electrode terminals 13 of the battery cells 1 and a plurality of connection parts 51 in order to connect the plurality of battery cells 1 in series and in parallel. 52. The lead plate 50 is connected to a lead plate 50A that connects four battery cells 1 arranged in two stages and two rows in two series and two parallels, and to both ends of a plurality of battery cells 1 that are connected in series to each other. It includes a lead plate 50B that connects two battery cells 1 in parallel.

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

Furthermore, in order to guide the partition wall 26 formed in the recess 23, the lead plate 50 has a groove 53 formed by bending a connecting portion 52 provided between the connecting portions 51 into a groove shape. The lead plate 50B has a linear groove 53 formed between the two connecting portions 51, so that the partition wall 26 can be guided into the groove 53. The lead plate 50A has four grooves 53 formed between the four connecting portions 51, and these grooves 53 are formed in criss-cross directions to guide the cross-shaped partition walls 26. That's what I do. Further, the lead plate 50A has a through hole 54 at a position facing the intersection 27 of the intersecting partition walls 26. In this lead plate 50A, a plurality of grooves 53 can be easily formed in cross-shaped directions by opening the through holes 54 at positions facing the intersections 27. The above-mentioned lead plate 50 has grooves 53 provided between the connecting parts 51 arranged in the partition wall 26, so that the connecting parts 52 of the lead plate 50 are arranged along the partition wall 26 while the plurality of connecting parts 51 can be brought close to the electrode terminal 13 of the battery cell 1 to ensure electrical connection. Another feature is that the lead plate 50 can be positioned at a fixed position by guiding the groove 53 to the partition wall 26.

The lead plate 50A shown in FIGS. 2 and 3 connects the electrode terminals 13 of four battery cells 1 arranged in two stages and two rows, but the lead plate limits the number of batteries arranged in multiple series and multiple parallels. do not. The lead plate can connect six battery cells arranged in three stages and two rows, or can connect eight battery cells arranged in four stages and two rows.
(Battery assembly 10)

The battery holder 2 shown in FIGS. 1 to 5 holds a plurality of battery cells 1 in a fixed position with an end holding part 6, and holds a plurality of battery cells 1 in a recess 23 provided in the end holding part 6. Electrode terminals 13 are connected by lead plates 50, and further, a closing plate 31 is fixed to the surface of the end holding part 6, and the end face side of the battery cell 1 is covered with the cell covering part 7 to form the battery assembly 10.

In the battery assembly 10 shown in FIGS. 2 to 5, a plurality of battery cells 1 are arranged in parallel in multiple stages and rows, and are placed in a fixed position by a battery holder 2. The battery pack 100 of this embodiment has ten battery cells 1 arranged in two stages and five rows, and these battery cells 1 are electrically connected in five series and two parallels. However, the present invention does not specify the number of battery cells 1 to be accommodated, nor does it specify the structure in which they are arranged in multiple rows and stages.

Note that the battery pack 100 shown in FIGS. 1 to 5 does not have a dual structure of a battery holder and an exterior case as in the conventional case, but uses the battery holder itself as the exterior case. This allows for further reduction in size and weight and cost. However, the present invention aims to avoid unintentional spread of fire to battery cells, and is not limited to the above-mentioned integrated structure of the battery holder and exterior case, but also has a double structure in which a separate exterior case is provided outside the battery holder. It goes without saying that this is a good idea.
(exhaust hole)

In the battery cell 1, an exhaust hole is provided in a sealing plate 3 provided with a convex electrode, and a safety valve is provided in this exhaust hole. This battery cell 1 maintains safety even if the internal pressure of the battery cell rises abnormally due to overcharging, internal short circuit, etc., by opening the safety valve and exhausting the internal gas from the exhaust hole. It's increasing. Such a safety valve is generally provided on the positive electrode side of a battery cell.

On the other hand, if a jet of high-pressure gas, flame, or the like is released from one of the battery cells, there is a concern that the high temperature of the jet may adversely affect other battery cells. Although the ejection time of the ejected body is relatively short, and the pressure and temperature of the ejected body are reduced in inverse proportion to the square of the distance, as shown in the cross-sectional view of FIG. Because the distance is relatively short, there is a concern that the ejected body will flow in as shown by the arrow and be directly exposed to the high temperature and pressure of the ejected body. In particular, in the case of cylindrical battery cells, the sealing plate 3 is fixed to the opening of the outer can 11 by caulking through an insulating resin, so if it is heated rapidly, the insulating resin at the caulked joint part There are concerns that it may have a negative impact on
(Gap closing wall 26A)

Therefore, in this embodiment, a gap closing wall 26A is provided so that even if the ejected body is discharged from any one battery cell, the influence on the adjacent battery cells is suppressed. As shown in the cross-sectional views of FIGS. 4 and 5, the battery holder 2 forms a gap closing wall 26A that protrudes so as to come into contact with the cell covering part 7 on the surface facing the cell covering part 7. . As a result, by providing the gap closing wall 26A between adjacent battery cells 1, a state is created in which high-temperature ejected bodies are discharged from the right battery cell 1A, as shown in the enlarged cross-sectional view of FIG. Also, the gap closing wall 26A can prevent the ejected body from moving to the left battery cell 1B. This gap closing wall 26A is interposed between adjacent battery cells 1 connected by lead plates 50. Further, the gap closing wall 26A is made to protrude from the upper surface of the partition wall 26. Therefore, the upper surface of the partition wall 26 is not the same plane, and only the upper surface of the partition wall 26 provided with the gap closing wall 26A is higher. Note that the gap closing 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 the ejected body can be dammed up. That is, it does not need to be airtightly closed.

Further, as described above, the battery cell 1 is provided with a safety valve on the positive electrode side. Therefore, the ejected body may be ejected from the positive electrode side. Therefore, a gap closing wall 26A is disposed between the battery cells 1 at a portion where the positive electrode side of the battery cell is adjacent to another battery cell. In this way, by providing the gap closing wall 26A on the positive electrode side where the safety valve is provided, even if the safety valve is opened, the gap closing wall will prevent the high temperature ejected material discharged from the safety valve from flowing into the adjacent battery cell. It can be suppressed with 26A, increasing safety.

In other words, a structure may be adopted in which no gap closing wall is provided between the negative electrode and adjacent battery cells. Generally, there is no safety valve on the negative electrode side, so there is no possibility of a high-pressure ejected body leaking from there.In general, on the negative electrode side, the outer can is formed of a single metal plate, and separate parts such as a sealing plate are not required. This is because there are no joints to protect because there is no tightening. In the battery pack 100 shown in FIG. 2, a gap closing wall 26A is provided only between the positive electrodes adjacent to each other. With this configuration, even if ejected bodies such as high-pressure gas are discharged from the positive electrode side, when considered as the ejecting side, the ejected bodies will not flow into the positive electrode side of the adjacent battery cell. Moreover, when viewed as a side receiving discharge, an advantage can be obtained that the joint portion of the sealing plate 3 can be protected from being exposed to the ejected body.

Further, as described above, the battery holder 2 has an open portion where the battery cell 1 held by the battery holder 2 faces the lead plate 50, and a lattice-shaped partition wall 26 is provided in this opening. By providing the gap closing wall 26A on the upper surface of this partition wall 26, the opening of the battery holder 2 is reinforced by the partition wall 26, and the upper surface of this partition wall 26 is partially protruded to close the gap closing wall 26A. By forming this structure, there is an advantage that the structure can be used as a safety measure against thermal runaway, and the structure can be made common and simplified.

As described above, the end holding portion 6 has the gap closing wall 26A partially protruding from the upper surface of the partition wall 26. Accordingly, the connecting portion 52 of the lead plate 50 is bent into a convex shape so as to match the upper surface of the partition wall 26 . That is, the connecting portion 52 of the lead plate 50 is bent so as to correspond to the upper surface shape of the partition wall 26, so that the connecting portion 52 is higher in the portion where the gap closing wall 26A is provided, and lower in other portions. I'm letting you do it.

However, in this configuration, there is a directionality in the arrangement posture of the lead plate. For example, as shown in FIG. 2, when a total of four battery cells, two battery cells with positive electrodes facing upward and two battery cells with negative electrodes facing upward, are placed adjacent to each other, these four battery cells 1 are In a configuration in which a gap closing wall 26A is provided between only one of the four battery cells that occur in the lead plate 50 to be connected, when the lead plate 50 is joined to the battery cell 1, Think about your posture. In this case, there may be four orientations in the rotational direction in which the rectangular lead plate is placed on the four battery cells. Among these, only one of the postures is a correct posture in which the gap closing wall 26A and the high connecting portion 52A are aligned, and the lead plate cannot be fixed correctly in the other postures. Therefore, when assembling the battery pack, it is necessary to adjust the lead plates so that they are in the correct orientation. Therefore, in the example of FIG. 2, the connecting portion 52 of the lead plate 50 is a connecting portion 52A that is raised in one direction (vertical direction in the figure), and a connecting portion 52B that is lower in the direction crossing this (horizontal direction in the figure). It is said that In other words, two of the four connecting parts 52, 52A, are made higher and are arranged in a straight line. With this lead plate 50, it is possible to correctly connect the battery cells in two positions, which provides the advantage of reducing errors during assembly. In this case, a gap will be created between the top surface of the partition wall 26 located between the negative electrodes and the connecting portion 52A of the lead plate 50, but originally the top surface of the partition wall 26 and the cell covering portion 7 This is a configuration in which a gap is formed between the negative electrode plates, and in a region where the negative electrode plates are adjacent to each other, it is not expected that ejected bodies will be ejected during thermal runaway, so this does not pose a problem.

As described above, by arranging the gap closing wall 26A while electrically connecting the battery cells 1 to each other with the lead plate 50, even if a high temperature ejected body is discharged from one battery cell, , it is possible to suppress the situation where the liquid flows into the other battery cell.
[Embodiment 2]

In the above example, an example was explained in which the gap closing wall 26A was configured to abut against the cell covering portion 7 via the lead plate 50. However, the present invention is not limited to this configuration, and may be configured such that the gap closing wall is brought into direct contact with the cell covering portion. Such an example is shown in FIGS. 7 and 8 as a battery pack 200 according to the second embodiment. In these figures, FIG. 7 shows an exploded perspective view of a battery pack 200 according to the second embodiment, and FIG. 8 shows an enlarged vertical cross-sectional view of a main part of this battery pack 200. In the battery pack 200 shown in these figures, the same members as those in the first embodiment described above are designated by the same reference numerals, and detailed description thereof will be omitted as appropriate.
(slit 56)

The lead plate 50 shown in FIG. 7 has a slit 56 formed therein. The lead plate 50 is fixed to the battery cell 1 with the slit 56 arranged in the gap closing wall 26A. In this way, by arranging the gap closing wall 26A to pass between the slits 56, the gap closing wall 26A can be directly connected to the cell covering portion 7 without intervening the lead plate 50, as shown in the cross-sectional view of FIG. It becomes possible to make it come into contact with. As shown in FIG. 7, the connecting portion 51 of the lead plate 50 is not electrically connected in the portion where the slit 56 is provided, but connects the upper surface of the partition wall 26 where the gap closing wall 26A is not provided with the connecting portion 52. Thus, the four connection parts 51 are electrically connected, and the four battery cells 1 are maintained at the same potential.

As described above, by providing the gap closing wall 26A between adjacent battery cells 1, even in the unlikely event that high temperature gas is discharged from the battery cell, the other adjacent battery cell By blocking the flow of the metal to the end face side, the risk of secondary fire can be reduced.

The battery pack according to the present invention can be used as a battery pack that improves safety by suppressing the spread of fire or similar fire caused by ejected bodies ejected from the end faces of battery cells when a battery cell is abnormal. It can be suitably used as a power source for electric tricycles, electric carts, cleaners, electric blowers, etc., as well as for storing electricity in homes and stores.

100, 200...Battery pack 1, 1A, 1B...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...Exterior can 13... Electrode terminal 21... End plate part 22... Insertion hole 23... Recessed part 24... Stopper part 25... Insulating wall 26... Division wall 26A... Gap closing wall 27... Intersection part 28... First boss 29... Second boss 31... Closing Plate 32... Covering area 33... Fitting convex portion 34... Convex line 35... Forming recess 38... Connection screw 39... Set screw 50, 50A, 50B... Lead plate 51... Connection section 52... Connection section; 52A... High connection section; 52B...Low connecting part 53...Groove part 54...Through hole 55...Output lead part 56...Slit

Claims (8)

a plurality of battery cells each having a positive electrode terminal and a negative electrode terminal on an end face extending in the longitudinal direction;
a battery holder that holds the plurality of battery cells in a posture parallel to each other in the 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 lead plate that connects the electrode terminals of adjacent battery cells,
a cell covering portion that covers a surface of the battery holder on which the lead plate is provided;
A battery pack comprising:
The battery holder has a gap closing wall that protrudes so as to come into contact with the cell covering portion on a surface facing the cell covering portion,
The battery holder has an opening that opens a portion where the battery cell held by the battery holder faces the lead plate, and the opening is provided with a grid-like intersection,
The upper surface of the intersection portion is partially protruded to form the gap closing wall ,
Each of the plurality of battery cells is provided with a safety valve on the positive electrode side,
A battery pack, wherein one of the plurality of battery cells has a positive electrode side adjacent to another battery cell, and the gap closing wall is arranged between the battery cells. The battery pack according to claim 1,
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 1 or 2,
A battery pack in which the gap closing wall is brought into contact with the cell covering portion via the lead plate. The battery pack according to claim 1 or 2,
The lead plate forms a slit,
A battery pack configured such that the gap closing wall is arranged in the slit. The battery pack according to any one of claims 1 to 4,
A battery pack in which the lead plate has a rectangular outer shape. The battery pack according to any one of claims 1 to 5 ,
A battery pack in which the gap closing wall is arranged between the plurality of battery cells at a portion where the positive electrodes are adjacent to each other. The battery pack according to any one of claims 1 to 6 ,
The battery holder includes:
an intermediate holding part that holds an intermediate portion of the plurality of battery cells;
A battery pack comprising: an end holding part that holds ends of the plurality of battery cells. The battery pack according to any one of claims 1 to 7 ,
A battery pack in which the plurality of battery cells have a cylindrical outer shape.

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