JP6859319B2 - Battery pack - Google Patents

Description

The present invention relates to a battery pack in which a plurality of battery cells are stored in a fixed position of a holder case, and more particularly to a battery pack in which an intermediate portion of the battery cells is stored in a state of being exposed inside the holder case.

In recent years, power generation using natural energy such as solar power and wind power has attracted attention. Compared to power generation methods that use limited fossil fuels such as petroleum and coal as energy, these power generation methods are further introduced as clean power generation methods that are friendly to the global environment and use renewable energy that does not deplete resources. It is expected to spread. However, this type of power generation has a problem that the amount of power generation is affected by the time zone of day and night and the weather. Therefore, in order to realize a stable power supply, there is an increasing demand for equipment for storing the generated power. In addition to power generation using renewable energy, in power generation such as thermal power generation and nuclear power generation, if the turbine is rotated for 24 hours to continue power generation, the power generated in the middle of the night will be supplied in the daytime when the amount of power used is high. There is a demand for equipment that stores electricity so that it can be stored.

As such a power storage device, a device including a battery pack in which battery cells such as a lithium ion secondary battery and a nickel hydrogen secondary battery that can be used repeatedly are connected in multiple series and in parallel is adopted. Among them, lithium-ion secondary batteries have been widely used in recent years because of their light weight, high electromotive force, and high energy density. In the battery pack, a large number of battery cells can be connected in series to increase the output voltage, and can be connected in parallel to increase the output current. In particular, due to the recent demand for larger capacities, the number of battery cells to be stored tends to increase. However, since the battery cell generates heat when charged and discharged with a large current, it is also important to ensure heat dissipation.

As a battery pack including a large number of battery cells, a battery pack including a battery holder for storing a cylindrical battery cell in a cylindrical battery storage portion has been developed (see Patent Document 1). This battery pack includes a battery holder formed by forming a large number of tubular battery storage portions in order to store a large number of battery cells. This battery holder is divided into two parts in the middle of the battery cells, and has a structure in which the battery cells are sandwiched and held from both sides by a pair of divided cases. The above battery holder is generally made of resin from the viewpoint of insulation and the like, and when each of such two divided cases is injection-molded with a mold, the number of tubular battery storage portions is used. As the number increases, the frictional resistance at the time of demolding increases. For this reason, even if an attempt is made to construct a battery holder for accommodating a large number of battery cells, there is a problem that mold molding becomes difficult and the manufacturing cost rises.

On the other hand, a battery pack having a structure in which only both ends are stored in the battery storage part and the middle part of the battery cell is exposed without storing the entire cylindrical battery cell in the battery storage part has also been proposed. (See Patent Document 2). This battery pack is provided with a tubular battery storage portion for accommodating an end portion of a battery cell on the inner surface of a pair of divided cases formed by dividing the battery holder into two parts. Since this battery holder inserts only the end portion of the battery cell into the battery housing portion, it has a feature that the intermediate portion of the battery cell can be exposed and the heat dissipation characteristics of this portion can be improved.

Japanese Unexamined Patent Publication No. 2007-317579 International Publication No. WO2012 / 132135

As shown in FIG. 12, the battery holder 92 that holds both ends of the battery cell in the battery storage portion has one end of the battery cell 91 inserted into the battery storage portion 93 of one of the split cases 92X (lower case in the figure). In this state, the other end of the battery cell 91 is inserted into the battery storage portion 93 of the other split case 92Y (upper case in the figure) and sandwiched from both sides. At this time, when the position of the other end of the battery cell 91, one end of which is inserted into the battery storage portion 93 of one of the split cases 92X, moves back and forth and left and right, the other end of the battery cell 91 is moved to the other split case 92Y. It becomes difficult to promptly guide the battery storage unit 93. In particular, when storing a large number of battery cells 91, it is necessary to insert the other ends of all the battery cells 91 into the battery storage portions 93 of the split cases 92Y facing each other at the same timing, which is troublesome. .. Unfortunately, this problem becomes more remarkable as the battery storage portion 93 is made shallower and the area where the battery cell 91 is exposed is widened.

That is, if the depth of the cylinder portion, which is the battery storage portion formed in the pair of cases, is deepened, the battery holder can easily identify the posture of the inserted battery and can be easily assembled, but the mold becomes complicated. This makes it difficult to remove the mold and increases the manufacturing cost. Further, the area of the battery cell exposed inside the battery holder is also reduced, and the heat dissipation characteristics are deteriorated. On the contrary, if the battery storage portion is shallow, the structure of the mold is simplified and it becomes easy to remove the mold. Therefore, the manufacturing cost can be reduced, and the area of the battery cells exposed inside the battery holder can be increased. However, while arranging a large number of battery cells in the fixed positions of the battery holder, both sides of the pair of facing cases are used. It becomes difficult to hold the battery so that it is sandwiched between the batteries, and the efficiency of the assembly work is reduced. As described above, the battery compartment is made shallow to make the battery holder and mold a simple structure, and both ends of the battery cell are quickly guided to the battery compartment of the battery holder consisting of a pair of cases. It was not possible to satisfy both of them at the same time because the characteristics of sandwiching the battery cells from both sides were contradictory to each other.

The present invention has been made in view of such a background, and one of the purposes thereof is to make the holder case a simple structure, simplify the structure of the mold, make it easy to remove the mold, and reduce the manufacturing cost. Further, it is an object of the present invention to provide a battery pack in which a large number of battery cells are arranged while being positioned between a pair of cases, and both ends of the battery cells can be easily held and held from both sides by the pair of cases.
Further, the present invention is to provide a battery pack capable of improving heat dissipation characteristics by exposing a wide area of the middle portion of the battery cell in the holder case while holding both ends of the battery cell in the holder case.

Means for Solving Problems and Effects of Invention

In order to achieve the above object, according to the battery pack according to the first aspect of the present invention, a plurality of battery cells 1 formed by closing the opening of a tubular and bottomed outer can 11 with a sealing plate 12. A holder case 2 is provided which holds the plurality of battery cells 1 in a posture parallel to each other and the electrode terminals 13 provided at both ends of each battery cell 1 in a posture of arranging them on the same surface. The holder case 2 has a first case 2X provided with a plurality of holding portions 21 inside for inserting and holding one end of the battery cell 1, and a holding portion for inserting and holding the other end of the battery cell 1. A second case 2Y in which a plurality of 21's are provided inside is provided, and a plurality of battery cells 1 are sandwiched between the first case 2X and the second case 2Y from both sides in the longitudinal direction to hold both ends of the plurality of battery cells 1. The structure is such that the intermediate portions of the plurality of battery cells 1 are exposed in the holder case 2 while being held by the portions 21. Further, the battery pack is arranged between the holding portion 21 of the first case 2X and the holding portion 21 of the second case 2Y, and has a positioning spacer 3 for holding and positioning the intermediate portion of the plurality of battery cells 1. I have. Further, the first case 2X and the second case 2Y include an end face plate portion 22 provided with a plurality of holding portions 21 on the inner side surface, and a peripheral wall 23 formed along the periphery of the end face plate portion 22 as a whole. The outer shape is substantially rectangular, and the facing opening edges of the peripheral walls 23 are connected to each other to form a hollow portion 20 inside which the intermediate portion of the battery cell 1 is exposed, and the first case 2X and the second case 2Y face each other. The positioning spacer 3 can be sandwiched between the peripheral walls 23 and arranged at a fixed position.

With the above configuration, the intermediate portions of the plurality of battery cells arranged between the first case and the second case are held and positioned by the positioning spacers, so that both ends of the battery cells are held in the first case and the second case. The battery cell can be pinched from both sides in the longitudinal direction while being guided to the holding portion of the battery. Therefore, both ends of the plurality of battery cells can be easily and easily guided to the holding portions of the first case and the second case, and the assembly work can be efficiently performed. Further, at the time of assembly, since a plurality of battery cells can be positioned by the positioning spacers arranged between the first case and the second case, the holding portions formed in the first case and the second case can be formed shallowly. As a result, the first case and the second case can be manufactured easily, easily, and at low cost by using a mold having a simple structure. Further, the first case and the second case are composed of an end face plate portion provided with a plurality of holding portions on the inner surface and a peripheral wall formed along the periphery of the end face plate portion, and the outer shape is substantially rectangular. By connecting the facing opening edges of the peripheral walls to each other, a plurality of battery cells can be arranged at a fixed position of the storage chamber formed inside while the holder case has a simple structure. Further, by sandwiching the positioning spacer between the peripheral walls of the first case and the second case facing each other, the positioning spacer can be arranged at an accurate position and the battery cell can be accurately positioned.

Further, according to the battery pack according to the second embodiment, the positioning spacer 3 is a perforated plate formed by penetrating the battery cell 1 and opening a plurality of insertion holes 3A for holding the intermediate portion of the battery cell 1. The battery cell 1 can be positioned by inserting the battery cell 1 into the insertion hole 3A. With the above configuration, while the positioning spacer has a simple structure, the battery cells can be fitted into the insertion holes opened in the perforated plate, and a plurality of battery cells can be reliably positioned.

Further, according to the battery pack according to the third embodiment, the holder case 2 can be molded with a thermosetting resin. With the above configuration, the first case and the second case have a simple shape, so that the thermosetting resin can be easily manufactured. In particular, by molding the holder case with a thermosetting resin, excellent heat resistance and chemical resistance can be realized.

Furthermore, according to the battery pack according to the fourth embodiment, the depth of the holding portion 21 of the first case 2X and the second case 2Y is set to 25% or less of the total length of the battery cell 1, and the thickness of the positioning spacer 3 is set to 25% or less. Can be 10% or less of the total length of the battery cell 1.

With the above configuration, the depth of the holding portion of the first case and the second case is made shallow, and the thickness of the positioning spacer is made thin, so that the area where the battery cell is exposed in the holder case is widened, which is effective. Can dissipate heat. In particular, by setting the depth of the holding portions of the first case and the second case to 25% or less of the total length of the battery cell and the thickness of the positioning spacer to be 10% or less of the total length of the battery cell, the outer circumference of the battery cell is set. The area of 40% or more of the surface can be exposed and heat can be effectively dissipated.

Furthermore, according to the battery pack according to the sixth embodiment, at least one of the first case 2X and the second case 2Y is provided with a stepped recess 23A for fitting the positioning spacer 3 along the opening edge of the peripheral wall 23. be able to. With the above configuration, the positioning spacer can be arranged in a fixed position by fitting the positioning spacer into the stepped recess provided along at least one opening edge of the first case or the second case.

Furthermore, according to the battery pack according to the seventh aspect, a pair of bus bar plates 4 arranged outside the end face plate portions 22 of the first case 2X and the second case 2Y can be further provided. In this battery pack, a plurality of battery cells 1 are arranged side by side in the same direction and stored in the holder case 2. In the first case 2X and the second case 2Y, a connection hole 24 penetrating the bottom surface of the holding portion 21 is provided as an end face plate portion 22. The electrode terminal 13 of the battery cell 1 can be exposed from the connection hole 24, and the electrode terminal 13 can be connected to the bus bar plate 4 to connect a plurality of battery cells 1 in parallel.

With the above configuration, a plurality of battery cells are arranged in the same direction and stored in a holder case, and the electrode terminals at the battery ends inserted into the holding portions of the first case and the second case are inserted through the connection holes opened in the end face plate portion. A plurality of battery cells can be easily connected in parallel by exposing the electrode terminals and connecting the electrode terminals to a bus bar plate arranged outside the end face plate portion. Further, since this battery pack arranges a pair of bus bar plates on the outside of the end face plates of the first case and the second case, the heat conducted from both ends of the battery cell is effectively dissipated through the bus bar plates. it can.

Furthermore, according to the battery pack according to the eighth embodiment, the pair of bus bar plates 4 are arranged outside the first bus bar plate 4X and the second case 2Y arranged outside the first case 2X. Each bus bar plate 4 is composed of 2 bus bar plates 4Y, and each bus bar plate 4 includes bent pieces 41, 43 bent along the peripheral wall 23 from the outer peripheral edge of the end face plate portion 22, and the tip portions of the bent pieces 41, 43 are formed. Further, the external connection portions 42 and 44 can be provided by bending. The first bus bar plate 4X has a bent piece 41 arranged on the first surface 2A, which is the side surface of the holder case 2 having a rectangular outer shape, and the second bus bar plate 4Y has a side surface facing the first surface 2A. The bent piece 43 can be arranged on the third surface 2C.

With the above configuration, by arranging the folded pieces of the pair of bus bar plates arranged on both sides of the holder case on the opposite side surfaces of the holder case, it is possible to surely prevent these bent pieces from interfering with each other. Further, even when a plurality of battery packs are externally connected, by arranging the positive and negative external connection portions on the opposite side surfaces of the holder case, it is possible to connect safely while surely preventing harmful effects such as short circuit.

Furthermore, according to the battery pack according to the ninth aspect, the holder case 2 is fitted to guide the bent piece 41 to the first surface 2A on which the bent piece 41 of the first bus bar plate 4X is arranged. A fitting recess 27 for guiding the bent piece 43 is provided on the third surface 2C provided with the recess 26 and on which the bent piece 43 of the second bus bar plate 4Y is arranged, and the fitting recess 27 is external to the fitting recess 27. A stepped surface 28 on which the connecting portion 44 is arranged can be formed.

With the above configuration, the bent pieces arranged on the first surface and the third surface of the holder case can be guided to the fitting recess and arranged in a fixed position while being reliably connected to the outside. In particular, by guiding the bent piece to the fitting recess recessed from the surface of the holder case, it is possible to prevent the bent piece, which is a metal piece, from protruding toward the surface side of the holder case, and it is effective to have an adverse effect such as a short circuit. Can be prevented. Further, since the fitting recess provided on the third surface of the holder case is provided with a stepped surface for arranging the external connection portion of the second bus bar plate, the external connection portion of the second bus bar plate is provided on this surface. You can reliably connect to the outside. For example, when connecting a plurality of battery packs in series, the external connection portion of the first bus bar plate of the adjacent battery pack is placed on the upper surface of the external connection portion of the second bus bar plate arranged on the stepped surface. It can be arranged in a stacked state and connected securely.

It is a perspective view of the battery pack which concerns on one Embodiment of this invention. FIG. 2 is a sectional view taken along line II-II of the battery pack shown in FIG. FIG. 3 is a sectional view taken along line III-III of the battery pack shown in FIG. It is an exploded perspective view of the battery pack shown in FIG. It is an exploded perspective view of the battery pack shown in FIG. 4 seen from the lower side. It is an exploded perspective view of the holder case of the battery pack shown in FIG. 7A to 7D are schematic cross-sectional views showing an assembly process of the battery pack shown in FIG. It is a partially enlarged exploded perspective view of the first bus bar plate. It is a partially enlarged exploded perspective view of the second bus bar plate. It is an enlarged sectional view of the main part which shows the connection process of a bus bar plate and a battery cell. It is sectional drawing which shows the state which a plurality of battery packs are connected in series. It is an exploded sectional view which shows the assembly process of the conventional battery pack.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiments shown below exemplify a battery pack for embodying the technical idea of the present invention, and the present invention does not specify the battery pack as the following. Further, the present specification does not specify the members shown in the claims as the members of the embodiment. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the components described in the embodiments are not intended to limit the scope of the present invention to the specific description unless otherwise specified, and are merely explanatory examples. It's just that. Further, in the following description, members of the same or the same quality are shown with the same name and reference numeral, and detailed description thereof will be omitted as appropriate. Further, each element constituting the present invention may be configured such that a plurality of elements are composed of the same member and the plurality of elements are combined with one member, or conversely, the function of one member is performed by the plurality of members. It can also be shared and realized.

The battery pack of the present invention can be used as a power source for a stationary power storage facility. For example, as a power storage device for a power plant, a power generation facility, a factory, or a public facility, it can be charged by solar power generation or wind power generation, or at midnight. It can be applied to a power storage device that charges with power and discharges when needed. In such an application, a plurality of battery packs can be connected and these can be connected in series and / or in parallel to increase the output to form a power storage device. The power storage device can control the charging and discharging of each battery pack by connecting a plurality of battery packs in a string and connecting a controller at the end. However, the battery pack of the present invention is not limited to the power source of such storage equipment, but is used as a power source for street lights that charge sunlight during the day and discharge it at night, and for a signal or computer server that is driven during a power failure. Needless to say, it can also be used as a backup power source for batteries, a backup power supply device for wireless base stations such as mobile phones, and the like.

1 to 6 show a battery pack according to an embodiment of the present invention. In these figures, FIG. 1 is a perspective view of the battery pack, FIG. 2 is a sectional view taken along line II-II of the battery pack of FIG. 1, FIG. 3 is a sectional view of the battery pack of FIG. 1 is an exploded perspective view of the battery pack, FIG. 5 is an exploded perspective view of the battery pack of FIG. 4 as viewed from below, and FIG. 6 is an exploded perspective view of the holder case.

In the battery pack 10 shown in these figures, the plurality of battery cells 1 formed by closing the openings of the tubular and bottomed outer can 11 with the sealing plate 12 and the plurality of battery cells 11 are arranged in parallel to each other. It also includes a holder case 2 that holds the electrode terminals 13 provided at both ends of each battery cell 1 in a posture of arranging them on the same surface. The holder case 2 has a first case 2X provided with a plurality of holding portions 21 inside for inserting and holding one end of the battery cell 1, and a holding portion for inserting and holding the other end of the battery cell 1. It is provided with a second case 2Y in which a plurality of 21's are provided inside. In the holder case 2, a plurality of battery cells 1 are sandwiched between the first case 2X and the second case 2Y from both sides in the longitudinal direction, both ends of the plurality of battery cells 1 are held by the holding portions 21, and the intermediate portion is held. It is exposed in the case 2. Further, the battery pack 10 is provided between the holding portion 21 of the first case 2X and the holding portion 21 of the second case 2Y, and includes a positioning spacer 3 that holds the intermediate portion of the battery cell 1 while positioning it. ing.

(Battery cell 1)
The battery cell 1 is a lithium ion secondary battery that can be charged and discharged. However, the battery cell is not limited to the lithium ion secondary battery, and may be a battery that can be charged and discharged, such as a nickel hydrogen battery or a nickel cadmium battery. Further, in the battery pack of this embodiment, a cylindrical battery is used, but the present invention is not limited to this, and a square battery or a flat battery may be used.

As shown in a partially enlarged view of FIG. 6, the battery cell 1 houses an electrode body (not shown) in a tubular and bottomed outer can 11, and is filled with an electrolytic solution to open the outer can 11. The portion is closed with a sealing plate 12. In the battery cell 1, the bottom surface of the outer can 11 which is both end faces and the sealing plate 12 which is closed in the opening of the outer can 11 in an insulated state are positive and negative electrode terminals 13.

In the battery cell 1 shown in FIG. 6, the outer can 11 is made of iron or an iron alloy to increase the strength, and the sealing plate 12 is a metal plate formed in a disk shape having a central concave shape without providing a convex electrode. Is used. Aluminum or an aluminum alloy can be used as such a sealing plate 12. The battery cell 1 having this structure can reduce the strength of the aluminum sealing plate 12 with respect to the iron outer can 11. Therefore, when a problem such as an abnormally high internal pressure occurs due to overcharging or an internal short circuit, the aluminum sealing plate 12 is preferentially opened to promptly release the internal gas or the like to the outside. It can be discharged to guarantee safety. However, although not shown, the battery cell may have a structure in which a convex electrode is provided on the sealing plate. This battery cell is provided with a safety valve on the sealing plate or the convex electrode, and when the internal pressure of the battery rises, the safety valve can be opened to exhaust the internal gas from the exhaust port.

(Holder case 2)
The holder case 2 shown in FIGS. 2, 3 and 6 houses a plurality of battery cells 1 in a posture parallel to each other. The plurality of battery cells 1 are arranged so as to have the same orientation. That is, in the figure, the bottom end of the outer can 11 is on the lower side, and the end side closed by the sealing plate 12 is on the upper side. The holder case 2 holds the electrode terminals 13 provided at both ends of each battery cell 1 in a fixed position in a posture of arranging them on the same surface.

As shown in FIG. 6, the holder case 2 is divided into a first case 2X and a second case 2Y in the longitudinal direction of the battery cell 1 and in the middle in the thickness direction. Each of the first case 2X and the second case 2Y is provided with a holding portion 21 inside for individually inserting and holding the end portions of the cylindrical battery cells 1. The first case 2X and the second case 2Y have an end face plate portion 22 provided with a plurality of holding portions 21 for inserting the end portions of the battery cell 1 on the inner side surface, and a peripheral wall formed along the periphery of the end face plate portion 22. It has 23 and. The first case 2X and the second case 2Y have a substantially rectangular outer shape as a whole, and the facing opening edges of the peripheral wall 23 are connected to each other.

(Holding unit 21)
The holding portion 21 is formed in a shape that allows the end portion of the battery cell 1 to be inserted and held. The holding portion 21 shown in the figure has a shape along the outer peripheral surface of the battery cell 1, preferably close to or in contact with the outer peripheral surface of the battery cell 1 so as to have no gap between the holding portion 21 and the outer peripheral surface of the battery cell 1. A plurality of recesses are provided inside the end face plate portion 22. The plurality of holding portions 21 are formed so that the battery cell 1 inserted therein can be held in a substantially vertical posture with respect to the end face plate portion 22. Here, since the battery cell 1 uses a cylindrical secondary battery, the holder case 2 forms a holding portion 21 having a cylindrical inside so that the cylindrical battery cell 1 can be stored. .. As shown in the exploded perspective view of FIG. 6, these holding portions 21 join the first case 2X and the second case 2Y so as to sandwich the first case 2X and the second case 2Y from both sides of the battery cells 1 to join the plurality of battery cells 1. It can be stored in a fixed position inside the holder case 2. However, the holding portion is a tubular portion having an internal shape that conforms to the outer shape of the battery cell, and a plurality of these tubular portions can be arranged side by side.

The plurality of holding portions 21 are provided inside the first case 2X and the second case 2Y in a predetermined arrangement, respectively. The number of holding portions 21 formed in the holder case 2 is determined by the number of battery cells 1 to be housed. In this embodiment, the holder case 2 is provided with 66 holding portions 21 in the first case 2X and the second case 2Y, respectively. The holding portions 21 of the holder case 2 shown in FIG. 6 are formed in nine rows from the second surface 2B toward the fourth surface 2D, and in each row, the holding portions 21 are directed from the first surface 2A to the third surface 2C. 7 to 8 pieces are arranged in a straight line at equal intervals, and 66 holding parts 21 are provided in total. Therefore, the holder case 2 has a structure capable of accommodating a maximum of 66 battery cells 1. Further, the holding portions 21 formed over multiple rows are arranged so that the battery cells 1 in the adjacent row are located between the adjacent battery cells 1 in one row, that is, in a staggered arrangement. The battery cell 1 can be arranged in a space-saving manner.

The depth of the holding portion 21 formed in the concave shape is 5 to 30%, preferably 10 to 25%, and more preferably 15 to 25% of the length of the battery cell 1. Further, by joining the battery cell 1 between the first case 2X and the second case 2Y so as to sandwich the battery cell 1 from both sides, both end portions of the battery cell 1 are housed and held by the two holding portions 21, and the battery cell is held. A hollow portion 20 is formed inside the holder case 2 so that the intermediate portion of 1 is exposed inside the holder case 2 and the intermediate portion of the battery cell is exposed inside the holder case 2. As a result, the intermediate portion of the battery cell 1 can be separated from each adjacent battery cell, so that the cooling effect of the battery cell can be improved.

Further, in the first case 2X and the second case 2Y, a connection hole 24 penetrating the bottom surface of the holding portion 21 is opened in the end face plate portion 22. The end face plate portion 22 exposes the electrode terminal 13 from the connection hole 24 opened on the outer surface in a state where the end portion of the battery cell 1 is inserted into the holding portion 21 provided inside. Further, as shown in FIGS. 2 and 3, the connection hole 24 is made smaller than the outer shape of the outer can 11 of the battery cell 1 inserted into the holding portion 21 to prevent the battery cell 1 from passing through. .. As a result, the end portion of the battery cell 1 inserted into the holding portion 21 can be stopped at a fixed position of the connection hole 24 without penetrating the end face plate portion 22. The electrode terminal 13 of the battery cell 1 exposed from the connection hole 24 of the end face plate portion 22 is connected to the bus bar plate 4 arranged outside the end face plate portion 22, which will be described in detail later.

In the first case 2X and the second case 2Y shown in FIGS. 4 to 6, a storage recess 25 for arranging the bus bar plate 4 is formed on the outer surface of the end face plate portion 22. In the first case 2X and the second case 2Y shown in the figure, the peripheral wall 23 provided around the end face plate portion 22 is also projected to the outside of the end face plate portion 22, and is formed by the protruding portion and the end face plate portion 22. The recess to be formed is used as a storage recess 25 as a storage space for the bus bar plate 4. In the holder case 2 shown in the figure, the bus bar plate 4 is arranged in the storage recess 25, and the outside of the storage recess 25 is closed by the cover member 5.

Further, although not shown, the holder case 2 can have a vent opening in the peripheral wall 23 which is a side surface. As a result, ventilation is performed inside and outside the holder case 2, and the heat dissipation characteristics of the battery cell 1 housed in the holder case 2 can be further improved.

(Molding resin)
Such a first case 2X and a second case 2Y are each formed by injection molding using a mold. The holder case 2 is made of a member having excellent insulating properties, preferably a resin. As such a resin, a thermoplastic resin such as PC (polypropylene), PP (polypropylene), or PBT, or a thermosetting resin such as unsaturated phenol resin or unsaturated polyester can be used. In the case of a thermosetting resin, it is formed by compression molding or injection compression molding.

The structure in which the holder case is molded with a thermoplastic resin can easily perform injection molding using a mold, and the manufacturing cost can be reduced by using an inexpensive thermoplastic resin. However, since the holder case may be heated to a high temperature when the battery cell is abnormal, it can be manufactured of thermoplastic resin according to the capacity and number of battery cells used, the usage environment, and the required heat resistance performance. it can.

On the other hand, in the structure in which the holder case 2 is molded with a thermosetting resin, the time for injecting the molten resin into the mold becomes longer during molding using a mold, and the holder case 2 is heated and cured after the injection. Since it requires a process, there is a problem that it cannot be efficiently mass-produced in a short time, and there is a problem that the manufacturing cost rises due to the use of an expensive thermosetting resin. However, in the battery pack of the present invention, since the plurality of battery cells 1 are arranged in a fixed position by interposing the positioning spacer 3 between the first case 2X and the second case 2Y constituting the holder case 2, the first case is used. Even if the holding portions 21 formed in the case 2X and the second case 2Y are made shallow, the holding portions 21 can hold both ends of the battery cell while sandwiching them from both sides. That is, by forming the holding portion 21 into which the end portion of the battery cell 1 is inserted shallowly, the amount of resin used is reduced while the mold has a simple structure, and the manufacturing cost is reduced while shortening the manufacturing time. It can be mass-produced. Further, since the holder case made of thermosetting resin has excellent heat resistance, as described above, even if the battery cell is heated to a high temperature due to ignition or smoke when the above occurs, it melts. Burning to adjacent battery cells is effectively prevented without being done. In addition, since the thermosetting resin is also excellent in chemical resistance, it is possible to prevent harmful effects caused by the electrolytic solution discharged from the battery cell. From the above viewpoints, here, a thermosetting resin is preferably used as the resin for producing the holder case.

(Positioning spacer 3)
The positioning spacer 3 is arranged between the holding portion 21 of the first case 2X and the holding portion 21 of the second case 2Y to hold the intermediate portion of the plurality of battery cells 1 and these battery cells 1 Identify the location of. The positioning spacer 3 shown in FIG. 6 is a perforated plate formed by penetrating the battery cell 1 and opening a plurality of insertion holes 3A for holding the intermediate portion of the battery cell 1. The insertion holes 3A opened in the positioning spacer 3 are provided at positions facing the holding portions 21 of the first case 2X and the second case 2Y arranged vertically. Further, the insertion hole 3A has an inner shape that contacts the outer peripheral surface of the battery cell 1 so that the intermediate portion of the battery cell 1 can be held at a fixed position. The positioning spacer 3 holds the intermediate portion of the battery cell 1 inserted into the insertion hole 3A so that the battery cell 1 can be positioned at a fixed position in the holder case 2.

In the above battery pack 10, while positioning the plurality of battery cells 1 with the positioning spacer 3, the first case 2X and the second case 2Y hold both ends of the battery cell 1 so as to be sandwiched from both sides. A large number of battery cells 1 can be easily inserted into the opposing holding portions 21 while being positioned. For example, as shown in FIG. 7, with the positioning spacer 3 arranged in the opening of the first case 2X, the battery cell 1 is inserted into the insertion hole 3A of the positioning spacer 3, and the end on the insertion side is the first. By inserting the battery cell 1 into the holding portion 21 of the case 2X, the battery cell 1 can be arranged in the first case 2X while being positioned (see FIG. 7B). In this state, the lower end of the large number of battery cells 1 arranged in the first case 2X is inserted into the holding portion 21 of the first case 2X, and the intermediate portion is positioned by the insertion hole 3A of the positioning spacer 3. Therefore, it is possible to eliminate the difficulty of being inserted into the holding portion 21 of the second case 2Y without the upper end portion moving back and forth and left and right. That is, in the large number of battery cells 1 arranged in the first case 2X, the position of the upper end portion is positioned by holding the intermediate portion in a fixed position by the positioning spacer 3, and the second case 2Y is moved. The upper end of the battery cell 1 can be reliably inserted into the holding portion 21 of the second case 2Y while being covered from above (see FIG. 7C). This structure can hold the battery cell while positioning it in substantially the same state as the battery storage portion that stores about half the length of the battery cell 1. Therefore, the opposite end can be quickly inserted into the opposite holding portion, and both ends of the battery cell 1 can be held so as to be sandwiched from both sides. As a result, work efficiency at the time of assembly can be improved.

By reducing the thickness of the positioning spacer 3, the battery cell 1 can be easily inserted, and the area exposed in the holder case 2 can be widened while holding the intermediate portion of the battery cell 1. it can. Therefore, the thickness of the positioning spacer can be preferably 10% or less of the total length of the battery cell. Such a positioning spacer 3 may be made of resin or metal.

The above positioning spacer 3 is sandwiched between the facing peripheral walls 23 of the first case 2X and the second case 2Y, and is arranged in the middle of the holder case 2. The holder case 2 shown in the figure is provided with a stepped recess 23A for fitting the positioning spacer 3 along the opening edge of the peripheral wall 23 of the first case 2X, which is the lower case. The holder case 2 is positioned by fitting the positioning spacer 3 into the stepped recess 23A of the first case 2X, and sandwiches the positioning spacer 3 between the facing peripheral walls 23 of the first case 2X and the second case 2Y. Wear it and fix it in place. However, the stepped recess can also be provided in the second case. In addition, the positioning spacer can be fixed to the holder case by bonding, screwing, or a locking structure.

As described above, the holder case 2 in which the plurality of battery cells 1 are housed is connected to the connecting boss 29 provided at the opposite positions of the first case 2X and the second case 2Y as shown in FIG. 39 is screwed in to fix the first case 2X and the second case 2Y. In the first case 2X shown in the figure, a connecting boss 29 is integrally formed on the end face plate portion 22 and the peripheral wall 23. However, the first case and the second case can also be connected to each other via connecting bolts and nuts.

(Busbar plate 4)
Further, the battery pack 10 of FIGS. 2 to 5 is provided with a bus bar plate 4 connecting electrode terminals 13 at both ends of a plurality of battery cells 1 housed in the holder case 2 on the upper and lower outer sides of the holder case 2. .. The bus bar plate 4 is a flat metal plate that covers the outside of the end face plate portion 22, and is a plurality of plates for connecting the electrode terminals 13 of the plurality of battery cells 1 that are exposed from the connection holes 24 of the end face plate portion 22. The through hole 40 is opened. These through holes 40 are opened at positions facing the connection holes 24 opened in the end face plate portion 22.

The bus bar plate 4 is electrically connected to the electrode terminals 13 of the plurality of battery cells 1 housed in the holder case 2. The battery pack 10 shown in the figure is the lower surface side of the first case 2X, which is the lower case of the holder case 2, and is the first bus bar plate 4X arranged outside the end face plate portion 22, and the upper case. It is provided with a second bus bar plate 4Y which is on the upper surface side of the two cases 2Y and is arranged outside the end face plate portion 22. These bus bar plates 4 have a shape and a size that cover the entire end face plate portion 22, and have a size that can connect the electrode terminals 13 of all the battery cells 1 housed in the holder case 2. .. The bus bar plate 4 is fixed to the holder case 2 via a set screw 38 penetrating the bus bar plate 4. With this structure, the bus bar plate 4 can be securely fixed in place on the holder case 2.

As shown in FIGS. 8 to 10, the bus bar plate 4 is connected to the battery cell 1 via the lead plate 45. The lead plate 45 shown in FIGS. 8 and 9 is a thin metal plate, and has a connecting hole 45A opened at a position facing the through hole 40 of the bus bar plate 4, and a connecting piece 46 located at the connecting hole 45A. , 47. The connecting pieces 46 and 47 are formed by being integrally connected to the lead plate 45. The lead plate 45 is fixed to the bus bar plate 4 so that the connecting pieces 46 and 47 are located in the through holes 40 opened in the bus bar plate 4. Three lead plates 45 are connected to the bus bar plate 4 shown in FIGS. 8 and 9.

In the bus bar plate 4, the connection pieces 46 and 47 of the lead plate 45 are welded to the electrode terminals 13 of the battery cell 1 and connected to the battery cell 1. Therefore, the connection pieces 46 and 47 are arranged at positions facing the connection terminals 13 exposed from the connection holes 24. As shown in FIG. 10, the connecting pieces 46 and 47 are formed in a shape and size to be welded to the connecting terminal 13 in a state where the welding rod 60 is pressed. Further, the lead plate 45 shown in FIG. 8 forms a fusing portion 48 between the opening edge of the connecting hole 45A and the connecting piece 46. The fusing portion 48 shown in the figure has an elongated linear shape and is formed in a crank shape, and has a structure capable of reliably disconnecting the electrode terminal 13 of the battery cell 1 from the lead plate 45 by fusing in a state where an overcurrent flows. There is. The lead plate 45 shown in the figure has an adhesive tape, which is a fixing member 49, attached to the surface of the fusing portion in order to protect the fusing portion 48 formed thinly. This adhesive tape is a tape that is melted by heat, and when the fusing portion 48 is fusing, the adhesive tape is also melted and cut.

As shown in FIG. 10, the bus bar plate 4 to which the lead plate 45 is fixed is arranged so as to be laminated on the outer surface of the end face plate portion 22, and the connection piece 47 of the lead plate 45 is a connection hole of the end face plate portion 22. It is arranged at 24. The connection piece 47 arranged in the connection hole 24 is welded to the electrode terminal 13 of the battery cell 1. At the time of welding, as shown in FIG. 10, the welding rod 60 presses the connection piece 47 of the lead plate 45 against the electrode terminal 13 exposed from the connection hole 24 of the end face plate portion 22 to weld. The welding rod 60 is welded while passing through the through hole 40 of the bus bar plate 4 and pressing the connection piece 47 against the electrode terminal 13 of the battery cell 1. As described above, the electrode terminals 13 at both ends of the plurality of battery cells 1 housed in the holder case 2 are connected to the first bus bar plate 4X and the second bus bar plate 4Y to connect the plurality of battery cells. 1s are connected in parallel.

Further, the bus bar plate 4 shown in FIGS. 4 and 5 includes bent pieces 41 and 43 bent along the peripheral wall 23 from the outer peripheral edge of the end face plate portion 22, and the tips of the bent pieces 41 and 43. The parts are further bent to form external connection parts 42 and 44. The battery pack 10 shown in FIGS. 1 to 5 is a side surface of the holder case 2 having a rectangular outer shape, and the bent piece 41 is arranged on the first surface 2A and the bent piece 41 is arranged on the third surface 2C. 43 is arranged. By arranging the folded pieces 41, 43 of the pair of bus bar plates 4 on the opposite side surfaces of the holder case 2 in this way, these bent pieces 41, 43 are prevented from interfering with each other.

In the first bus bar plate 4X, the bent piece 41 is arranged along the first surface 2A of the holder case 2. The bent piece 41 is formed so as to rise from the lower surface side of the first case 2X along the first surface 2A, and the tip portion is bent in the horizontal direction to form an external connecting portion 42. The holder case 2 has a fitting recess 26 for guiding the bent piece 41 on the first surface 2A on which the bent piece 41 of the first bus bar plate 4X is arranged. By guiding the bent piece 41 to the fitting recess 26 in this way, it is possible to prevent the bent piece 41 from protruding toward the surface side of the holder case 2 while arranging the bent piece 41 at a fixed position. There is.

In the second bus bar plate 4Y, the bent piece 43 is arranged along the third surface 2C of the holder case 2. The bent piece 43 is formed so as to hang down from the upper surface side of the second case 2Y along the second surface 2C, and the tip portion is bent in the horizontal direction to form the external connecting portion 44. The holder case 2 has a fitting recess 27 for guiding the bent piece 43 on the third surface 2C on which the bent piece 43 of the second bus bar plate 4Y is arranged. Further, the fitting recess 27 is formed with a stepped surface 28 on which the external connecting portion 44 is arranged. By guiding the bent piece 43 and the external connecting portion 44 to the fitting recess 27 in this way, the bent piece 43 and the external connecting portion 44 are arranged at fixed positions, and the bent piece 43 and the external connecting portion 44 are arranged. Is prevented from protruding toward the surface side of the holder case 2. Further, on the stepped surface 28, the external connection portion 44 can be reliably externally connected.

(Cover member)
Further, as shown in FIGS. 1 to 6, the battery pack 10 is located outside the upper surface side and the lower surface side of the holder case 2 to which the bus bar plate 4 is fixed, and has a cover member 5 for covering the bus bar plate 4. I have. The cover member 5 shown in the figure covers and insulates the surface of the bus bar plate 4. The cover member 5 is preferably made of an insulating member, preferably made of resin. As a result, insulation and weight reduction can be realized at low cost. Also, considering durability and thermal conductivity, a metal cover member such as aluminum can be used. In this case, the surface of the metal cover member may be covered with an insulating member such as a laminated film or vinyl, or an insulating paint may be applied to insulate the cover member.

The cover member 5 has a shape and size that covers the upper and lower surfaces of the holder case 2. The cover member 5 shown in the figure includes a flat plate-shaped closing plate portion 51 along the outer shape of the holder case 2 and a cover portion 52 connected to the periphery of the closing plate portion 51. The cover portion 52 is locked and fixed to a locking convex portion 31 provided on the outer peripheral surface of the holder case 2. The cover portion 52 shown in FIGS. 2 to 5 has a locking hole opened as a locking portion 53 for locking the locking convex portion 31. The cover member 5 locks the cover portion 52 to the holder case 2. It is locked to the convex portion 31 in a locked state and fixed at a fixed position.

The cover member 5 shown in FIGS. 1 to 5 includes a first cover member 5X that covers the outside of the first case 2X side, and a second cover member 5Y that covers the outside of the second case 2Y side. There is. The first cover member 5X is provided with a cover portion 52 so as to cover the four side surfaces of the first case 2X. The second cover member 5Y is provided with a cover portion 52 facing three of the four side surfaces of the second case 2Y except the first surface 2A. The second cover member 5Y is fixed to the second surface 2B to the fourth surface 2D by the above-mentioned locking structure, and on the first surface, passes through the bent piece 43 of the second bus bar plate 4Y. It is open without providing the cover part 52 so that it can be made.

The above battery pack 10 is assembled by the following steps shown in FIG.
(1) As shown in FIG. 7A, the positioning spacer 3 is arranged in the opening of the first case 2X. The positioning spacer 3 is fixed in place by, for example, its outer peripheral edge being arranged in a fitted state in a stepped recess 23A formed along the opening edge of the peripheral wall 23 of the first case 2X.
(2) As shown in FIG. 7B, the battery cell 1 is inserted into the insertion hole 3A of the positioning spacer 3 arranged in the opening of the first case 2X, and the end on the insertion side is held by the first case 2X. It is inserted into the portion 21. In this state, the lower end of the large number of battery cells 1 arranged in the first case 2X is inserted into the holding portion 21 of the first case 2X, and the intermediate portion is positioned by the insertion hole 3A of the positioning spacer 3. Fixed in place.
(3) As shown in FIG. 7C, the second case 2Y is lowered while being covered from above, and the upper end portion of the battery cell 1 is guided to the holding portion 21 of the second case 2Y. At this time, since the upper ends of the plurality of battery cells 1 are fixed at fixed positions, the upper ends can be quickly guided and inserted into the holding portion 21 of the second case 2Y. The first case 2X and the second case 2Y are connected to each other in a state where both ends of the plurality of battery cells 1 are held by the respective holding portions 21, and the plurality of battery cells 1 are housed inside the holder case 2. ..
(4) Further, as shown in FIG. 7D, after arranging the first bus bar plate 4X on the lower surface side of the holder case 2 and connecting one electrode terminal 13 of the plurality of battery cells 1, the first bus bar plate The first cover member 5X is arranged below the 4X and connected to the holder case 2. Further, after arranging the second bus bar plate 4Y on the upper surface side of the holder case 2 and connecting the other electrode terminals of the plurality of battery cells 1, the second cover member 5Y is placed above the second bus bar plate 4Y. Arrange and connect to the holder case 2.

As shown in FIG. 6, the battery pack 10 described above houses the battery cells 1 in 65 of the 66 holding portions 21 provided in the holder case 2, excluding one. That is, in this battery pack 10, 65 battery cells 1 having a battery capacity of 4.62 Ah / cell are connected in parallel via a bus bar plate 4, and the output voltage is a large capacity of about 3 V to 4.15 V. It constitutes a battery pack 10. It goes without saying that the number, arrangement, and connection of the battery cells 1 housed in the holder case 2 are not limited to this, and can be changed depending on the required voltage and output capacity.

Further, in the above battery pack 10, a plurality of battery packs 10 can be connected in series as shown in FIG. In FIG. 11, the first bus bar plate arranged on the left side surface of the battery pack 10 located on the right side is connected to the external connecting portion 44 of the second bus bar plate 4Y arranged on the right side surface of the battery pack 10 located on the left side. It shows a state in which the external connecting portion 42 of 4X is connected. The external connecting portions 42, 44 that are laminated to each other are fixed to the holder case 2 by screwing the connecting screw 61 in the fitting recess 27. In this way, by connecting the facing external connecting portions 42, 44 of the battery packs adjacent to each other inside the fitting recess 27, it is possible to connect while surely preventing unintended contact with the outside.

The present invention is a battery pack in which a plurality of battery cells are held in a hollow shape in a holder case, and can be suitably used as a power source for a stationary power storage facility or as a backup power source for various battery devices. ..

1 ... Battery cell 2 ... Holder case 2X ... 1st case 2Y ... 2nd case 2A ... 1st surface 2B ... 2nd surface 2C ... 3rd surface 2D ... 4th surface 3 ... Positioning spacer 3A ... Insertion hole 4 ... Bus bar Plate 4X ... First bus bar plate 4Y ... Second bus bar plate 5 ... Cover member 5X ... First cover member 5Y ... Second cover member 10 ... Battery pack 11 ... Exterior can 12 ... Seal plate 13 ... Electrode terminal 20 ... Hollow portion 21 ... Holding portion 22 ... End face plate portion 23 ... Peripheral wall 23A ... Step recess 24 ... Connection hole 25 ... Storage recess 26 ... Fitting recess 27 ... Fitting recess 28 ... Step surface 29 ... Connecting boss 31 ... Locking convex Part 38 ... Set screw 39 ... Connecting screw 40 ... Through hole 41 ... Folded piece 42 ... External connecting part 43 ... Folded piece 44 ... External connecting part 45 ... Lead plate 45A ... Connecting hole 46 ... Connecting piece 47 ... Connecting piece 48 ... Fusing part 49 ... Fixing member 51 ... Closing plate part 52 ... Cover part 53 ... Locking part 60 ... Welding rod 61 ... Connecting screw 91 ... Battery cell 92 ... Battery holder 92X ... Split case 92Y ... Split case 93 ... Battery storage part

Claims (8)

A plurality of battery cells in which the opening of a tubular and bottomed outer can is closed with a sealing plate,
A holder case that holds the plurality of battery cells in a posture parallel to each other and the electrode terminals provided at both ends of each battery cell in a posture of arranging them on the same surface.
With
The holder case
A first case in which a plurality of holding portions for inserting and holding one end of the battery cell are provided inside.
A second case is provided with a plurality of holding portions inside for inserting and holding the other end portion of the battery cell.
The plurality of battery cells are sandwiched between the first case and the second case from both sides in the longitudinal direction, both ends of the plurality of battery cells are held by the holding portions, and an intermediate portion of the plurality of battery cells is held. Has a structure that allows the battery to be exposed in the holder case.
Further, a positioning spacer is provided between the holding portion of the first case and the holding portion of the second case to hold and position the intermediate portion of the plurality of battery cells .
The first case and the second case include an end face plate portion provided with a plurality of the holding portions on the inner side surface and a peripheral wall formed along the periphery of the end face plate portion, and the overall outer shape is substantially rectangular. As a shape, the facing opening edges of the peripheral wall are connected to each other to form a hollow portion inside which the intermediate portion of the battery cell is exposed.
A battery pack formed by sandwiching the positioning spacer between the peripheral walls facing the first case and the second case and arranging them in a fixed position. The battery pack according to claim 1.
The positioning spacer is a perforated plate formed by penetrating the battery cell and opening a plurality of insertion holes for holding an intermediate portion of the battery cell, and the battery cell is inserted into the insertion hole to insert the battery cell. A battery pack that is designed to be positioned. The battery pack according to claim 1 or 2.
A battery pack in which the holder case is molded of a thermosetting resin. The battery pack according to any one of claims 1 to 3.
A battery pack in which the depth of the holding portion of the first case and the second case is 25% or less of the total length of the battery cell, and the thickness of the positioning spacer is 10% or less of the total length of the battery cell. The battery pack according to claim 1.
At least one of the first case and the second case is a battery pack provided with a stepped recess for fitting the positioning spacer along the opening edge of the peripheral wall. The battery pack according to claim 1.
Further, it is provided with a pair of bus bar plates arranged outside the end face plate portions of the first case and the second case.
The plurality of battery cells are arranged side by side in the same direction and stored in the holder case.
In the first case and the second case, a connection hole penetrating the bottom surface of the holding portion is opened in the end face plate portion to expose the electrode terminal of the battery cell from the connection hole, and the electrode terminal is exposed. A battery pack that is connected to the bus bar plate and the plurality of battery cells are connected in parallel. The battery pack according to claim 6.
The pair of bus bar plates are composed of a first bus bar plate arranged outside the first case and a second bus bar plate arranged outside the second case, and each bus bar plate has an end face plate portion. It is provided with a bent piece bent along the peripheral wall from the outer peripheral edge of the above, and the tip of the bent piece is further bent to form an external connection part.
The first bus bar plate has the bent piece arranged on the first surface which is the side surface of the holder case having a rectangular outer shape.
The second bus bar plate is a battery pack in which the bent piece is arranged on a third surface which is a side surface facing the first surface. The battery pack according to claim 7.
The holder case is provided with a fitting recess for guiding the bent piece on the first surface on which the bent piece of the first bus bar plate is arranged, and the folding piece of the second bus bar plate is provided. A battery pack having a fitting recess for guiding the bent piece on the third surface on which the bent piece is arranged, and a stepped surface for arranging the external connection portion in the fitting recess.

Images