JP2020095778A - Battery pack - Google Patents

Abstract

To prevent a thin fuse link 3C from being broken due to vibration or shock and improve shock resistance of a battery pack.SOLUTION: Metal plate bus bars 3, for electrically connecting a plurality of batteries 1 arranged in a position by a battery holder 2, has fixed terminals 3A connected to electrode terminals of the batteries 1, base units 3B connecting the fixed terminals 3A, and fuse links 3C connected between the fixed terminals 3A and the base units 3B. In the base units 3B of the bus bar 3, fuse link connecting units 3Ba connecting base portions of the fuse links 3C are provided with first fitting units 3I. The battery holder 2 is provided with second fitting units 2C connected to the first fitting units 3I. The second fitting units 2C are connected to the first fitting units 3I. The fuse link connecting units 3Ba are connected to the battery holder 2 so as not to move relative to each other.SELECTED DRAWING: Figure 3

Description

The present invention relates to a battery pack in which a plurality of batteries arranged at fixed positions in a battery holder are connected in series or in parallel by a bus bar, and in particular, a battery pack in which a fuse link that is blown by an overcurrent of the battery is provided in the bus bar. Regarding

In a battery pack in which a plurality of batteries are connected in series or in parallel by a bus bar, a fuse link is provided in the bus bar to prevent battery overcurrent. (See Patent Documents 1 and 2)
The bus bar is a metal plate that connects batteries in series or in parallel, and is manufactured by cutting one metal plate. The bus bar connects a base portion for connecting batteries in series or in parallel with a fixed terminal connected to an electrode terminal of the battery with a fuse link. Since the fixed terminal is connected to the base portion via the fuse link, the fixed terminal is designed to blow when the current of the battery, that is, the current flowing through the fixed terminal becomes larger than the set current. Since the set current at which the fuse link is blown can be adjusted by the electric resistance of the fuse link, the fuse link made of a metal plate having high conductivity is made thin to adjust the set current. The fuse link is made thin so as to have a large electric resistance so as to generate heat and melt down when a set overcurrent flows.

JP, 2005-141801, A JP, 2016-066455, A

The fuse link is heated by the overcurrent Joule heat and blown. Joule heat is specified by the product of the square of the current and the electrical resistance. Therefore, the fuse link adjusts the electric resistance to specify the set current to be blown. The electric resistance of the fuse link is adjusted by narrowing the fuse link. Since the bus bar is made of a metal plate having a high conductivity, that is, a flow of electricity easily, a thin fuse link is used to increase the electric resistance. The thin fuse link has a drawback that it is easily broken due to the impact or vibration of the battery pack falling.

The present invention was developed to solve the above drawbacks. An important object of the present invention is to make a fuse link thin so as to be blown by a set overcurrent, prevent it from being broken by vibration or impact, and endure it without losing the fuse function in various applications. It is to provide a battery pack having excellent impact resistance.

A battery pack according to an aspect of the present invention includes a plurality of rechargeable batteries, a battery holder in which each battery is arranged in a fixed position, and a metal plate bus bar fixed to an electrode terminal of the battery. The bus bar has a plurality of fixed terminals connected to the electrode terminals of the battery, a base portion, and a fuse link having a tip connected to the fixed terminal and a root portion connected to the base portion. The base portion has a fuse link connecting portion formed by connecting the base portions of the fuse links, and the fuse link connecting portion is provided with a first fitting portion. The battery holder has a second fitting portion connected to the first fitting portion and a fuse link connecting portion, and the second fitting portion is connected to the first fitting portion, The fuse link connecting portion is connected to the battery holder.

The above battery pack prevents the thin fuse link that blows at the set current from being broken by vibration or shock, improves shock resistance, and can be used safely in various applications without losing the fuse function. Realize the characteristics. This feature is that the battery pack described above is provided with the first fitting portion at the fuse link connecting portion that connects the base portions of the fuse links, and the first fitting portion is provided at the battery holder. This is because the second fitting portion is connected and the fuse link connecting portion is connected to the battery holder so as not to move to the battery holder. The battery holder places both the battery and the fuse link connection in place to prevent relative movement between the fuse link and the battery. When the fuse link and the battery move relative to each other due to shock or vibration, the thin fuse link is deformed and damaged, but in the above battery pack, the thin fuse link and the battery move relative to each other even if the battery pack is shocked by being dropped. The damage to the fuse link is prevented.

In the battery pack according to an aspect of the present invention, the first fitting portion may be a fitting hole, and the second fitting portion may be a connecting rib formed integrally with the battery holder. Further, in a battery pack of a certain aspect, the first fitting portion provided in the fuse link connecting portion is provided in the vicinity of the fuse link root portion, or the distance (k) between the first fitting portion and the fuse link root portion. Is less than or equal to 5 times the lateral width (W) of the fuse link, or the fuse link connecting portion located between the adjacent fixed terminals is provided with the first terminal portion, and the first fitting portion is the fuse link. The connection portion may be disposed on an extension line of the fuse link root portion.

Further, in a battery pack according to an aspect of the present invention, an electrode window for exposing an electrode terminal of a battery housed in a fixed position is provided in a battery holder, and the battery holder is provided with a supporting surface at a position facing the inner surface of the fuse link. Can be provided to place the fuse link in contact with or in close proximity to the support surface, or the electrode window can be square and the support surface can be located outside the opening edge of the electrode window.

1 is a schematic exploded perspective view of a battery pack according to an embodiment of the present invention. It is a vertical cross-sectional view of the battery holder of the battery pack shown in FIG. It is a front view which shows the state which fixed the bus bar of the battery holder shown in FIG. It is a rear view which shows the state which fixed the bus bar of the battery holder shown in FIG. FIG. 2 is a front view of a bus bar of the battery pack shown in FIG. 1. It is a partially expanded sectional view of the bus bar shown in FIG. It is a partially expanded sectional view of the bus bar shown in FIG. It is a partially expanded sectional view of the battery holder of the battery pack shown in FIG. It is an expanded sectional view of the center part of the battery holder of the battery pack shown in FIG. It is a front view of the holder unit of the battery pack shown in FIG. It is a schematic circuit diagram which shows the connection state of the battery of the battery pack shown in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies a battery pack for embodying the technical idea of the present invention, and the present invention does not specify the battery pack to the following. Further, the present specification does not specify the members shown in the claims as the members of the embodiment. Unless otherwise specified, 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 thereto, but merely illustrative examples. Nothing more. The sizes and positional relationships of members shown in the drawings may be exaggerated for clarity of explanation. Further, in the following description, the same names and reference numerals indicate the same or similar members, and detailed description thereof will be appropriately omitted. Further, each element constituting the present invention may be configured such that a plurality of elements are configured by the same member and one member also serves as a plurality of elements, or conversely, the function of one member is performed by a plurality of members. It can be shared and realized.

The battery pack of the present invention is mainly used as a power source for power. This battery pack is used, for example, as a power source for electric devices driven by motors such as electric tools, electric-assisted bicycles, electric motorcycles, electric wheelchairs, electric tricycles, and electric carts. However, the present invention does not specify the use of the battery pack, but various electric devices other than electric devices, such as cleaners, radios, lighting devices, digital cameras, video cameras, and various other electric devices used indoors and outdoors. It can be used as a power source for equipment.

The exploded perspective view of FIG. 1 shows a battery pack according to an embodiment of the present invention. The battery pack of this figure has a plurality of rechargeable batteries 1, a battery holder 2 for arranging the plurality of batteries 1 in a fixed position, and a plurality of batteries 1 arranged in a fixed position in the battery holder 2 in series and in parallel. And a bus bar 3 connected to the. The battery holder 2 has a plurality of batteries 1 arranged in parallel with each other, and both ends thereof are arranged in the same plane and arranged in a fixed position. Further, the battery pack is assembled by housing a battery holder 2 in which a plurality of batteries 1 are arranged at fixed positions in an outer case (not shown).

(Battery 1)
In the battery pack shown in the figure, the battery 1 is a cylindrical battery. The cylindrical battery has an electrode body housed in a cylindrical outer can, filled with an electrolytic solution, and the opening of the outer can is sealed with a sealing plate. In the cylindrical battery, the bottom surface of the outer can, which is both end surfaces, and the convex electrode provided in the central portion of the sealing plate are used as positive and negative electrode terminals. A cylindrical battery having positive and negative electrode terminals on both end surfaces is arranged in parallel with the battery holder 2, the electrode terminals on both ends thereof are exposed on both surfaces of the battery holder 2, and connected in series with the bus bar 3 in parallel. It In the illustrated battery pack, the battery 1 is a cylindrical battery, but the present invention does not specify the battery as a cylindrical battery, but may be a prismatic battery, for example. The battery is a non-aqueous electrolyte secondary battery 1 such as a lithium ion battery. However, the present invention does not specify the battery as a lithium-ion battery, but can be used for all non-aqueous electrolyte secondary batteries, nickel-hydrogen batteries, and other secondary batteries currently used and to be developed.

(Battery holder 2)
The battery holder 2 is molded in a predetermined shape from a resin such as a thermoplastic resin which is an insulating material. The battery holder 2 can be preferably made of resin having excellent flame retardancy. As such a resin, for example, PC (polycarbonate) or PP (polypropylene) can be used.

As shown in the exploded perspective view of FIG. 1 and the cross-sectional view of FIG. 2, the battery holder 2 has a plurality of batteries 1 inserted into the battery housing portion 4 and arranged in parallel at a fixed position. The battery 1 is inserted into the battery housing portion 4, the electrode terminals provided on both end surfaces are arranged on the same plane, and exposed on both surfaces of the battery holder 2. The battery holder 2 is provided by partitioning the battery housing portion 4 with a partition wall 5. The partition wall 5 is in thermal contact with the outer peripheral surface of the battery 1. The partition wall 5 thermally coupled to the battery 1 conducts the heat generated by the battery 1 and absorbs the heat generated by the battery 1. The partition wall 5 that divides the battery housing portion 4 is located between the adjacent batteries 1, and its surface is brought into contact with the surface of the battery 1 to be thermally coupled to the battery 1. Deploy. Since the battery 1 is inserted into the battery housing portion 4 partitioned by the partition wall 5 and arranged at a fixed position, the inner surface has an inner shape along the outer peripheral surface of the battery 1. In the battery holder 2 shown in the figure, the cylindrical battery is inserted into the battery housing portion 4 and arranged at a fixed position, so that the battery housing portion 4 has a cylindrical inner shape. The cylindrical battery housing 4 has an inner diameter slightly larger than the outer diameter of the cylindrical battery, and is thermally coupled to the cylindrical battery and arranged at a fixed position. Since the battery housing portion 4 is partitioned by the partition walls 5, the partition walls 5 arranged between the batteries 1 have a surface along the surface of the cylindrical battery.

The battery holder 2 shown in FIGS. 1 and 2 has a shape in which a plurality of battery accommodating portions 4 are arranged in parallel in a “bale-stacked state” in multiple rows and multiple stages. The battery holder 2 is composed of a partition wall 5 between the batteries, and an outer peripheral wall 9 formed integrally with the partition wall 5 and provided on the outer periphery of the battery holder 2. The battery holder 2 has a battery storage portion 4 arranged on the outer peripheral portion between the outer peripheral wall 9 and the partition wall 5, and a battery storage portion 4 disposed inside the partition wall 5. The partition wall 5 and the outer peripheral wall 9 have a battery contact surface along the surface of the battery 1 and are thermally coupled to the battery 1 and arranged in a fixed position.

The battery holder 2 shown in the figure has the battery storage portions 4 arranged in a stacked state. This battery holder 2 has a feature that the battery 1 can be arranged in a space-efficient manner to make the whole compact. Further, by saving the resin in the valley portion, the amount of the resin used can be reduced, the manufacturing cost can be reduced, and the weight can be reduced. However, in the battery holder, batteries arranged in multiple stages and multiple rows can be arranged vertically and horizontally, and the batteries can be arranged at intersections in a grid pattern.

In the battery holder 2 of FIG. 2, 112 batteries 1 are arranged in 8 rows and 14 columns. In the drawing, one row of batteries 1 arranged in the vertical direction is arranged in a zigzag shape, and the batteries 1 in the adjacent rows are arranged in a valley portion of the zigzag, and are arranged in a bales stacking state. In the battery holder 2, the partition walls 5 are arranged between the batteries 1 arranged in multiple stages and multiple rows. In other words, the battery housing portion 4 is provided by the partition walls 5, and the batteries 1 are arranged between the partition walls 5. Of heat is conducted to the partition wall 5.

In the battery holder 2, the partition wall provided at the center is a heat insulating partition wall 5A. The adiabatic partition wall 5A is located in the center of the battery holder 2 and divides the batteries 1 on both sides into two blocks on the left and right in the figure to prevent heat diffusion between the blocks. The adiabatic partition wall 5A is divided into two blocks as a whole, and further absorbs heat generated by the batteries 1 arranged on both sides to reduce the temperature rise of the battery 1 in the central portion. The heat insulating partition wall 5A divides the battery 1 into two blocks on both sides between the batteries 1 (rows A and B in FIG. 2) in the central portion. Since the adiabatic partition walls 5A are provided with the opposing partition walls 5B on both sides of the air layer 6, the partition walls 5A are thicker than the partition walls 5 and the inter-battery distance (S1) arranged on both sides is the battery arranged in blocks divided on both sides. It becomes larger than the distance (S2). The adiabatic partition wall 5A provided in the central portion prevents the heat diffusion between the blocks by dividing the entire battery 1 into blocks on both sides even in a state where the amount of heat generated by the battery 1 increases due to a continuous large current. In addition, the heat is dissipated while insulating and effectively prevents the temperature of the battery 1 in the central portion from rising. The heat insulation division partition wall 5A is provided with opposing partition walls 5B on both sides of the air layer 6 which is not sealed. The opposing partition wall 5B has one surface thermally coupled to the battery 1 to absorb the thermal energy of the battery 1, and the other surface exposed to the air layer 6 to radiate the absorbed thermal energy into the air.

In the battery holder 2 shown in FIGS. 1 and 2, the batteries 1 are arranged in multiple stages and multiple rows, and are in the form of blocks elongated in the horizontal direction in the drawings. In the horizontally long battery holder 2, the temperature of the battery 1 is high in the central portion in the longitudinal direction, so the heat insulating partition wall 5A is arranged in the central portion in the longitudinal direction. The heat insulating partition walls 5A provided between the batteries 1 arranged in a zigzag form the zigzag shape and the batteries 1 are arranged on both sides. The opposing partition wall 5B shown in the enlarged cross-sectional view of FIG. 9 is connected at the closest position 50 where the adjacent batteries 1 are closest to each other, and the inner width is maximized in the region surrounded by the three batteries 1, so that the inner volume is increased. Is getting bigger.

In the battery holder 2 of FIGS. 1 and 2, the heat insulating partition wall 5A is arranged at the center in the longitudinal direction, and the heat insulating partition wall 5A has a shape extending in a direction intersecting the battery holder 2 in the longitudinal direction. The pair of opposed partition walls 5B are provided with an air layer 6 separated from each other in the longitudinal direction of the battery holder 2. As shown in the enlarged cross-sectional view of FIG. 9, the batteries 1 arranged in the bales are arranged such that the centers of the three batteries 1a, b, c are arranged at the apexes of a triangle. In the enlarged cross-sectional view of the figure, an air layer 6 is provided between the batteries 1a and 1b arranged in the longitudinal direction of the battery holder 2 with the opposing partition walls 5B spaced apart (d). A pair of opposed partition walls 5B are connected as the closest position 50 between the batteries 1b and 1c. A partition wall 5 having no air layer is arranged between the batteries 1c and 1a.

The battery holder 2 of FIG. 9 has a structure in which a pair of opposing partition walls 5B arranged between the batteries 1b and 1c are connected as the closest position 50, that is, the opposing partition walls 5B in this portion are thickened as a two-layer structure, It is possible to increase the inter-battery distance (S1) by providing an interval (d) in the opposing partition wall 5B between the batteries 1a and 1b. Therefore, the air layer 6 can be provided between the opposed partition walls 5B while locally connecting the pair of opposed partition walls 5B. Since the battery holder 2 connecting the pair of opposing partition walls 5B can connect the partition walls 5 arranged on both sides thereof via the heat insulating partition wall 5A in an integrated structure, while providing the air layer 6 on the heat insulating partition wall 5A in the central portion. The entire battery holder 2 can be integrated. Therefore, it is not necessary to connect the separately formed battery holders 2 on both sides of the adiabatic partition wall 5A with an outer case or the like while providing the adiabatic partition wall 5A having the air layer 6 in the central portion.

In the battery holder 2 of FIG. 2, the heat insulating partition wall 5A is arranged so as to extend to the facing surface (upper and lower surfaces in the drawing). That is, the entire length of the heat insulating partition wall 5A is made substantially equal to the thickness of the battery holder 2. This battery pack can effectively prevent the temperature rise of the battery 1 arranged in the central portion of the elongated battery holder 2 by the heat insulating partition wall 5A. However, in the battery pack of the present invention, the adiabatic partition wall 5A does not necessarily have to be arranged in the entire width of the battery holder 2, and the length of the adiabatic partition wall 5A is 1/3 or more of the thickness of the battery holder 2, preferably 1 It is also possible to prevent the temperature rise of the battery 1 in the central portion by setting //2 or more.

The battery holder 2 shown in FIG. 1 is composed of a pair of holder units divided in the middle. In this holder unit, electrode windows 7 exposing the electrode terminals at both ends of the battery 1 are opened at both ends of a battery housing part 4 for inserting and holding the battery 1, and the electrodes of the battery 1 exposed from the electrode windows 7 are opened. The shape is such that the bus bar 3 can be connected to the terminal. In the illustrated battery holder 2, the electrode window 7 exposing one electrode terminal of the battery 1 has a rectangular shape. The electrode window 7 exposing the other electrode terminal is circular. Further, the electrode window 7 is smaller than the outer shape of the battery 1 so that the battery 1 does not pass through, and the battery 1 is arranged in the battery housing portion 4.

The battery holder 2 shown in FIG. 1 is composed of a pair of holder units 2A divided in the middle. In this holder unit 2A, electrode windows 7 exposing the electrode terminals at both ends of the battery 1 are opened at both ends of a battery housing portion 4 in which the battery 1 is inserted and held. The shape is such that the bus bar 3 can be connected to the electrode terminals. In the battery holder 2 shown in the figure, the electrode window 7 exposing the negative electrode terminal of the battery 1 is rectangular, and the electrode window 7 exposing the positive electrode terminal is circular. The electrode window 7 is smaller than the outer shape of the battery 1 so that the battery 1 does not pass through, and the battery 1 is arranged in the battery housing portion 4.

Further, in the battery holder 2, the length of the battery housing portion 4 formed by the pair of holder units 2A, that is, the thickness of one holder unit 2A is approximately half the total length of the battery 1. In the holder unit 2A, the battery 1 is inserted into the battery housing 4 provided by the pair of holder units 2A in a state of being connected to each other, and covers the entire outer peripheral surface of the battery 1. In this way, the structure in which the entire outer peripheral surface of the battery 1 is covered with the battery housing portion 4 can effectively prevent burning between adjacent batteries.

(Bus bar 3)
The bus bar 3 in FIG. 1 connects a plurality of batteries 1 arranged in multiple stages and multiple rows in series and in parallel. The bus bar 3 is a conductive metal plate, and has a plurality of fixed terminals 3A connected to the electrode terminals of the battery 1, a base portion 3B for connecting the plurality of batteries 1 in series and parallel via the fixed terminals 3A, and a tip. The fuse link 3C is connected to the fixed terminal 3A and the base portion is connected to the base portion 3B. The bus bar 3 is manufactured by cutting one metal plate with a mold and bending it. 2 is a front view of the bus bar 3 arranged on the front surface of the battery holder 2, and FIG. 3 is a front view of the bus bar 3 arranged on the rear surface of the battery holder 2. The battery holder 2 has eight bus bars 3 arranged on the front surface and the back surface, and each battery 1 is connected in parallel and in series by the bus bar 3.

The fixed terminal 3A is connected to the electrode terminal of the battery 1 by spot welding. The fixed terminal 3A is provided with a weld 3E at the tip of the step 3D. Further, the fixed terminal 3A is provided with a gap 3F between the fixed terminal 3A and the base portion 3B to separate the welded portion 3E from the base portion 3B. The welded portion 3E is arranged inside the electrode window 7 provided in the battery holder 2 and spot-welded and connected to the electrode terminal of the battery 1. The step portion 3D projects the welding portion 3E separated from the base portion 3B toward the electrode terminal, and connects the welding portion 3E to the electrode terminal inside the electrode window by contacting the welding portion 3E. The weld 3E protruding toward the electrode terminal through the step 3D is inserted into the electrode window 7 of the battery holder 2 and contacts the electrode terminal arranged on the inner surface of the electrode window 7. The welded portion 3E is provided with two protrusions 3G locally protruding toward the electrode terminal on both sides of the slit 3H, and the protrusion 3G is spot-welded and connected to the electrode terminal. The slit 3H reduces the reactive current and efficiently welds the convex portion 3G to the electrode terminal.

The fixed terminal 3A includes a first fixed terminal 3Aa connected to the base portion 3B via a fuse link 3C and a second fixed terminal 3Ab directly connected to the base portion 3B without a fuse link. Become. The first fixed terminal 3Aa connects the fuse link 3C between the step portion 3D and the welding portion 3E. The second fixed terminal 3Ab connects the step portion 3D directly to the base portion 3B. In the battery pack of the figure, the fuse link 3C is connected to the negative electrode terminal of the battery 1, so the first fixed terminal 3Aa is connected to the negative side of the battery 1 and the second fixed terminal 3Ab is connected to the battery 1. Connect to the positive electrode terminal.

The fuse link 3C is provided at a position facing the supporting surface 2B provided on the battery holder 2, in other words, the battery holder 2 is provided with a supporting surface 2B facing the fuse link 3C. The fuse link 3C is located at a position in contact with or close to the supporting surface 2B of the battery holder 2, and the supporting surface 2B is prevented from being deformed or damaged. The step of the stepped portion 3D is set so that the fuse link 3C contacts or comes close to the support surface 2B. That is, the stepped portion 3D sets the stepped portion of the stepped portion 3D so that the fuse link 3C contacts or comes close to the support surface 2B in a state where the welded portion 3E is fixed to the electrode terminal. In this bus bar 3, the welded portion 3E is fixed to the electrode terminal so that the fuse link 3C can come into contact with or come close to the supporting surface 2B. In the battery holder 2 of FIG. 1, the electrode window 7 has a quadrangular shape, and the supporting surface 2B of the fuse link 3C is provided outside the opening edge of the electrode window 7. The battery holder 2 in which the electrode window 7 is formed in a quadrangle and the supporting surface 2B is provided on the outer side thereof has a characteristic that the supporting surface 2B is provided at a position facing the entire surface of the fuse link 3C, and the deformation or damage of the entire fuse link 3C can be reliably prevented. ..

The base portion 3B is another portion of the bus bar 3 except the fixed terminals 3A and the fuse links 3C, and connects all the batteries 1 connecting the fixed terminals 3A in parallel and in series. As shown in FIG. 5, the bus bar 3 is formed by pressing a single metal plate, cutting it into a shape in which a plurality of fixed terminals 3A and fuse links 3C are arranged, and bending the fixed terminals 3A. A base portion 3B is provided between the outer side of and the adjacent fixed terminals 3A. The bus bar 3 is located between the fixed terminals 3A adjacent to each other, and the base portion 3B connecting the root portions of the fuse links 3C is used as the fuse link connecting portion 3Ba.

The fuse link connecting portion 3Ba is provided with a first fitting portion 3I connected to the battery holder 2 in order to prevent relative movement with the battery holder 2. The first fitting portion 3I is connected to the second fitting portion 2C provided on the battery holder 2. The second fitting portion 2C is connected to the first fitting portion 3I, and the fuse link connecting portion 3Ba is connected to the battery holder 2 so as not to move relative to each other. The structure in which the fuse link connecting portion 3Ba and the battery holder 2 do not move relative to each other prevents relative movement between the battery 1 and the fuse link 3C. Since the battery 1 is arranged at a fixed position of the battery holder 2 and the fuse link 3C is connected to the fuse link connecting portion 3Ba, the fuse link 3C is connected to the battery 1 via the battery holder 2 so as not to move relative to each other. Because. The structure in which the battery 1 and the fuse link 3C do not move relative to each other can prevent the fuse link 3C from being deformed when the battery pack is impacted or vibrated. Therefore, even if the battery pack receives a shock such as dropping, the fuse link 3C can be prevented from breaking.

In the bus bar 3 shown in FIGS. 6 and 7, the first fitting portion 3I is used as a fitting hole, and the second fitting portion 2C is a connecting rib formed in the battery holder 2. The fitting hole is provided by cutting the bus bar 3, and the connecting rib is formed integrally with the battery holder 2. The outer shape of the connecting rib is almost equal to the inner shape of the fitting hole, but is sized to be inserted. In the illustrated bus bar 3, the fitting hole has a circular shape and the connecting rib has a cylindrical shape. Therefore, the inner diameter of the fitting hole is slightly larger than the outer diameter of the connecting rib. In this structure, a connecting rib is inserted into the fitting hole at the time of assembly, and the fuse link connecting portion 3Ba is connected to the battery holder 2 so as not to move relative to each other to prevent relative movement between the fuse link 3C and the battery 1. The deformation of the fuse link 3C can be reliably prevented. This structure has a feature that it can be easily assembled. In addition, since the connecting rib can be integrally formed in the process of forming the battery holder 2 by cutting the metal plate to be the bus bar 3 to form the fitting hole, the manufacturing process can be simplified. However, in the present invention, although not shown, the first fitting portion 3I is a fitting convex portion, and the second fitting portion 2C is a fitting concave portion or a fitting hole into which the fitting convex portion can be fitted. You can also

In the bus bar 3 of FIGS. 5 to 7, the first fitting portion 3I is arranged near the root portion of the fuse link 3C. In this bus bar 3, the distance (k) between the first fitting portion 3I and the root portion of the fuse link 3C is set to 5 times or less of the lateral width (W) of the fuse link 3C, so that the deformation of the fuse link 3C can be further reduced. Further, in the bus bar 3 shown in the figure, the first fitting portion 3I provided in the fuse link connecting portion 3Ba is arranged on the extension line of the root portion of the fuse link 3C, and the first fitting portion 3I is connected to the fuse link 3C. Place it close to the base of. This structure is also characterized in that the first fitting portion 3I and the second fitting portion 2C can more reliably prevent the deformation of the fuse link 3C and effectively prevent the deformation and damage.

The bus bar does not necessarily need to be provided with the first fitting portion in all the fuse link connecting portions. In the bus bar 3 of FIGS. 5 to 7, the first fitting portion 3I is provided only in the fuse link connecting portion 3Ba between the adjacent fixed terminals 3A, and the fuse link connecting portion 3Ba arranged in the outer peripheral portion has the first fitting portion 3I. No fitting part is provided. The fuse link connecting portion 3Ba on the outer peripheral portion is provided with a through hole 3J in the nearby base portion 3B, and the connecting rib of the battery holder 2 is inserted into this through hole 3J so that the through hole 3J and the connecting rib move relative to each other. This prevents the fuse link 3C from being deformed.

The bus bar 3 has a positioning hole 3K in the base portion 3B between the fixed terminals 3A located on the left and right in FIGS. The bus bar 3 is arranged at a fixed position of the battery holder 2 by inserting a connecting rib formed integrally with the battery holder 2 into the positioning hole 3K. The positioning hole 3K and the connecting rib also have an effect of preventing relative movement between the bus bar 3 and the battery holder 2 while arranging the bus bar 3 at a fixed position of the battery holder 2.

In each bus bar 3 arranged on the surface of the battery holder 2, the batteries 1 arranged in the vertical direction in the figure are connected in parallel, and the batteries 1 horizontally separated from each other are connected in series. .. The busbars 3 arranged on the back surface of the battery holder 2 are connected to the busbars 3 arranged on both sides and arranged in a row in the vertical direction in parallel, and the busbars 3 connected in parallel and in series to the two rows of the batteries 1. It consists of a bus bar 3. The bus bar 3 that connects the batteries 1 in two rows in parallel and in series connects the batteries 1 in each row in parallel and connects the batteries 1 in the adjacent row in series, like the bus bar 3 on the surface of the battery holder 2. doing.

The bus bar 3 has a first fixed terminal 3Aa connected to one electrode terminal of the battery 1 via a fuse link 3C. FIG. 11 shows a schematic circuit diagram in which a plurality of batteries 1 are connected in parallel and in series. In the battery pack having the circuit configuration shown in this circuit diagram, a fuse link 3C is connected to the negative side of each battery 1. Each battery 1 is connected to the minus side because the fixed terminal 3A of the bus bar 3 is connected to the plus side and the minus side and the fuse link 3C is connected to the first fixed terminal 3Aa connected to the minus side. The fuse link 3C is connected to one half of the first fixed terminals 3Aa.

The bus bar 3 is spot-welded or laser-welded to connect the fixed terminal 3A to the electrode terminal of the battery 1. The battery holder 2 is provided with positioning recesses for molding the bus bar 3 at fixed positions on both sides. FIG. 8 is an enlarged front view of the lower left portion of FIG. The batteries 1 shown in this figure are arranged in multiple rows by connecting the batteries 1 arranged in multiple stages (arranged vertically in the diagram) via a bus bar 3 (indicated by a chain line) in parallel with each other. The batteries 1 (which are arranged in the left-right direction in the drawing) are connected in series. However, the bus bar 3 can also connect the batteries 1 arranged in multiple stages in series and connect the batteries 1 arranged in multiple rows in parallel. The busbars 3 are arranged on both sides of the air layer provided in the heat insulating partition wall, and are arranged on both sides of the battery holder 2 without sealing the air layer, and connect the batteries 1 in series and in parallel.

The above battery pack has a feature that it can prevent the thermal runaway of the battery. As shown in FIG. 11, in a battery pack in which a plurality of batteries 1 are arranged close to each other in multiple stages and multiple rows, and are connected in series and in parallel by a bus bar 3, one of the batteries 1 causes thermal runaway and abnormal heat generation. Then, the thermal energy of the battery 1 that has run out of heat is thermally conducted to the adjacent battery 1 to cause the adjacent battery 1 to run out of heat. When thermal runaway is induced in the adjacent battery 1, the thermal energy generated is significantly increased and the safety is reduced. The induction of thermal runaway occurs with a higher probability between batteries connected in parallel (hereinafter referred to as parallel batteries) than between batteries connected in series (hereinafter referred to as series batteries). This is because the batteries 1 connected in parallel are heated by the thermally runaway battery 1, and a large short-circuit current flows through the thermally runaway battery 1. Internal short-circuiting is a major cause of thermal runaway of the battery 1. Therefore, a large short-circuit current flows in the battery 1 connected in parallel with the internal short-circuited thermal run-away battery 1 to generate heat due to Joule heat. Since the Joule heat increases in proportion to the square of the current, a large short-circuit current has an extremely large amount of heat generation and causes the temperature of the battery 1 to rise rapidly. The fuse link connected to each battery can be set to a maximum current so as to be blown by an excessive short-circuit current, so that thermal runaway of the battery can be prevented.

In the parallel battery 1 next to the battery 1 that has abnormally generated heat due to thermal runaway, large thermal energy from the battery 1 that has abnormally generated heat is conducted through the partition wall, and the battery 1 itself also abnormally generates heat due to an excessive short-circuit current. The temperature rises rapidly. On the other hand, the series battery 1 connected in series next to the battery 1 that has abnormally generated heat due to thermal runaway, through the battery 1 that has generated abnormal heat even if thermal energy is transmitted from the battery 1 that has generated abnormal heat No short-circuit current flows and no Joule heat is generated. For this reason, the series battery 1 connected in series with the battery 1 that has generated abnormal heat is less likely to induce thermal runaway than the parallel battery 1 connected in parallel, and does not burn due to thermal runaway.

In the battery holder 2 of FIG. 9, in order to prevent the thermal runaway of the battery 1 from being induced, a heat insulating layer 10 arranged between the battery 1 and the battery 1 is provided at a specific portion of the partition wall. The heat insulating layer 10 insulates a specific part of the partition wall to prevent the thermal runaway caused by the abnormal heat generation of the battery 1 and to prevent the battery 1 from the thermal runaway. The heat insulating layer 10 is provided in the approaching portion 5C of the partition wall between the parallel batteries 1 to insulate the parallel batteries from each other and prevent the thermal runaway between the batteries connected in parallel. The heat insulating layer 10 is not provided in the partition walls 5 between the series batteries 1, and in the partition walls between the series batteries, the heat energy of the battery 1 that has abnormally generated heat is conducted to reduce the temperature of the battery 1 that has abnormally generated heat.

The heat insulating layer 10 provided in the approaching portion 5C of the partition wall between the parallel batteries 1 cuts off thermal energy conducted from the battery 1 that has abnormally generated heat to the adjacent parallel battery 1 to prevent induction of thermal runaway. Since the thermal runaway of the battery 1 is more likely to occur in the battery 1 arranged adjacently and connected in series, that is, in the parallel battery 1 arranged adjacently and connected in parallel than the series battery 1, The heat conduction energy between the parallel batteries 1 is blocked by the heat insulating layer 10 provided in the approaching portion 5C of the partition wall between the parallel batteries 1.

The series batteries 1 that are connected in series and adjacent to each other, in which thermal runaway is hard to be induced, conduct heat by the partition wall provided between them, and the heat energy of the battery 1 that has abnormally generated heat is conducted to the adjacent series battery 1, The temperature of the battery 1 that has abnormally generated heat is lowered. The partition walls 5 between the series batteries are not provided with the heat insulating layer 10 like the approaching portions 5C of the partition walls between the parallel batteries 1, and the heat energy of the battery 1 which is abnormally heated by making the both surfaces heat-bonded to the surface of the battery 1 is provided next. It conducts heat to the series battery 1 to radiate heat. The partition wall 5 between the series batteries without the heat insulating layer 10 efficiently conducts the heat energy of the battery 1 that abnormally generates heat to the adjacent series battery 1 and radiates the heat, so that the temperature of the battery 1 that abnormally generates heat can be promptly lowered. There are features.

The battery holder 2 described above conducts the heat energy of the battery 1 that has abnormally generated heat to the adjacent series battery 1 via the partition wall 5 between the series batteries when any of the batteries 1 causes thermal runaway and abnormal heat generation. Then, the temperature of the abnormal heat generating battery 1 is rapidly lowered, and the heat energy which is thermally conducted by the heat insulating layer 10 is cut off at the approaching portion 5C of the partition wall between the adjacent parallel batteries 1 where thermal runaway is easily induced. Preventing thermal runaway of the battery 1. The thermal energy of the thermally runaway battery 1 does not conduct equally to both the adjacent series and parallel batteries 1. That is, the series battery 1 adjacent to the battery 1 that has abnormally generated heat due to thermal runaway conducts the thermal energy of the battery 1 that has abnormally generated heat to reduce the temperature of the battery 1 that has abnormally generated heat. The heat insulating layer provided in the vicinity of the partition walls between the batteries 1 limits the thermal energy for heat conduction to prevent induction of thermal runaway. Further, in the battery pack in which the fuse links are connected to the respective batteries, the thermal runaway can be more effectively prevented by fusing the fuse links with a short current.

The approaching portion 5C of the partition wall between the parallel batteries 1 is provided with a concave portion on the surface, and the heat insulating layer 10 is provided between the parallel battery 1 and the surface of the battery 1. The recess is on the inner surface of the battery housing portion 4, that is, the inner surface of the partition wall, and has a slender shape extending in the longitudinal direction of the battery 1. The concave portion provided on the surface of the approaching portion of the partition wall between the parallel batteries 1 forms the heat insulating layer 10 of the heat insulating layer 10 between the parallel battery 1 and the surface of the battery 1. Due to the heat insulating effect of the heat insulating layer 10, the battery 1 that abnormally generates heat is generated. Limits heat transfer from. The concave portion in the figure is provided with a heat insulating layer 10 having a uniform thickness along the arc of the outer peripheral surface of the battery 1 with the bottom surface being a curved surface along the outer peripheral surface of the battery 1.

In the battery holder 2 of FIG. 2, the heat insulating layer 10 having an even width is provided on both sides at the thinnest part of the approaching portion 5C of the partition wall between the parallel batteries 1. The heat energy of the battery 1 that has abnormally generated heat is conducted to the adjacent battery 1 via the partition wall, but the heat energy conducted to the maximum in the thinnest portion is the largest. The structure in which the heat insulating layer 10 is arranged in the thinnest part of the approaching portion 5C of the partition wall between the parallel batteries 1 reduces the thermal energy that is thermally conducted from the thinnest part to the adjacent battery 1, and the batteries connected in parallel. It can effectively prevent the thermal runaway of 1. Furthermore, the heat insulating layer 10 can improve the heat insulating property by making the recess deep and increasing the area facing the battery 1. Further, the heat insulating layer 10 has an elongated shape extending in the longitudinal direction of the battery 1 to improve heat insulating properties.

The heat insulating layer 10 extending in the longitudinal direction of the battery 1 has a total length of, for example, 30% or more, preferably 50% or more, and more preferably 80% or more of the total length of the battery 1. In addition, the heat insulating layer 10 has a structure in which its end is opened to the end of the battery housing 4 to ventilate the internal air to the outside of the battery holder 2, so that the heat insulating property can be improved. Furthermore, since the heat insulating property of the heat insulating layer 10 can be improved by widening the opening width in the circumferential direction, the opening width of the heat insulating layer 10 is, for example, 1/20 or more of the outer circumference of the battery 1, preferably 1/. It is 10 or more, 1/4 or less, and optimally about 1/7. Further, the heat insulating layer 10 provided in the thinnest portion of the approaching portion of the partition wall between the parallel batteries is opened with the same width on both sides of the thinnest portion as the center. The heat insulating layer 10 has a characteristic that the heat insulating property can be optimized with respect to the opening width. This is because the heat insulating layer 10 is arranged at the portion where the thermal energy of heat conduction is the largest.

The heat insulating layer 10 limits the heat conduction between the parallel batteries to be small, and controls the heat conduction of the battery 1 that has abnormally generated heat to an ideal state. The heat insulating layer 10 is provided on the partition wall approaching portion 5C between the parallel batteries 1, and is not provided on the partition wall between the series batteries. The battery holder 2 dissipates the heat energy of the battery 1 that has abnormally generated heat due to thermal runaway to the batteries 1 that are connected in series via the partition between the series batteries, and the parallel battery 1 that is prone to thermal runaway easily approaches the parallel battery 1. Prevents thermal runaway with 5C. The heat insulating layer 10 provided on the partition wall can most efficiently prevent the thermal runaway of both the batteries 1 connected in parallel and the batteries 1 connected in series in a state where any one of the batteries 1 abnormally generates heat. First, the length in the longitudinal direction, the opening width, and the depth of the recess are adjusted.

In the battery holder 2 described above, the heat insulating layer 10 is provided in the approaching portion 5C of the partition between the parallel batteries 1 without providing the heat insulating layer 10 in the partition between the series batteries. As a result, the heat conduction of the approaching portions 5C of the partition walls between the parallel batteries 1 is less than the heat conduction of the partition walls 5 between the series batteries, so that it is possible to prevent burning of the batteries 1 that have generated abnormal heat. The battery holder 2 can limit the heat conduction of the approaching portion 5C between the parallel batteries to be smaller than the heat conduction of the partition wall between the series batteries to prevent the battery 1 from burning. In addition, the heat insulating property of the heat insulating layer 10 provided in the approach portion 5C of the partition wall between the parallel batteries may be made larger than the heat insulating property of the partition wall between the series batteries, that is, the approach portion of the partition wall between the parallel batteries. A heat insulating layer is provided on both of the partition walls between the series batteries, and the heat insulating property of the heat insulating layer provided on the partition wall between the parallel batteries 1 is equal to that of the heat insulating layer 10 provided on the partition wall between the series batteries. Can be larger than. The heat insulating property of the heat insulating layer 10 is increased by increasing the width and increasing the length in the longitudinal direction of the battery 1 to increase the facing area of the battery 1, and increasing the depth of the recess, that is, the thickness of the heat insulating layer 10. it can. Therefore, in the battery holder 2, the area of the heat insulating layer 10 provided in the approaching portion 5 of the partition wall between the parallel batteries 1 facing the battery 1 is larger than that of the heat insulating layer 10 of the partition wall between the series batteries, and the parallel battery 1 The heat insulating layer 10 provided in the approaching portion 5C of the partition wall between the series batteries is made thicker than the heat insulating layer 10 of the partitioning wall between the series batteries so that the heat insulating property of the approach portion 5C of the partition wall between the parallel batteries 1 between the series batteries is increased. It can be made larger than the heat insulating property of the partition wall.

(Exterior case)
The outer case 11 shown in FIG. 1 accommodates a battery holder 2 in which a plurality of cylindrical batteries are arranged at fixed positions. The exterior case 11 shown in the figure is divided into a main body case 11A and a lid case 11B, and a storage portion for storing the battery holder 2 is formed inside. The body case 11A shown in FIG. 1 has a box shape having a depth capable of accommodating substantially the entire battery holder 2. The outer case 11 is connected by ultrasonic welding or bonding the end faces of the peripheral walls provided in the main body case 11A and the lid case 11B. Although not shown, the main body case and the lid case can be connected by screwing a set screw through one case and screwing into a boss provided in the other case.

Furthermore, the outer case can house a circuit board in addition to the battery holder 2. Electronic components such as a protection circuit can be mounted on the circuit board. The protection circuit may include a detection circuit that detects the voltage, the remaining capacity, and the temperature of each cylindrical battery, and a switching element that is switched on and off according to the data of the battery 1 detected by this detection circuit. Further, in the battery pack containing the circuit board, the output connector connected to the circuit board can be fixed to the outer case. The output connector has an output terminal and a signal terminal, can be charged and discharged through the output terminal, and can communicate with a device set through the signal terminal. However, the battery pack may have a structure in which the output terminals and the signal terminals are fixed to the circuit board without providing an output connector, and these connection terminals are exposed from the bottom case for external connection. it can.

INDUSTRIAL APPLICABILITY The present invention can be effectively used for a battery pack in which a large number of batteries 1 are housed in a battery holder 2 and fuse links are connected to the batteries to improve safety.

1, 1a, 1b, 1c... Battery 2... Battery holder 2A... Holder unit 2B... Support surface 2C... Second fitting portion 3... Bus bar 3A... Fixed terminal 3Aa... First fixed terminal 3Ab... Second fixed terminal 3B... Base part 3Ba... Fuse link connecting part 3C... Fuse link 3D... Step part 3E... Welding part 3F... Gap 3G... Convex part 3H... Slit 3I... First fitting part 3J... Through hole 3K... Positioning hole 4... Battery housing 5... Partition 5A... Adiabatic partition 5B... Opposing partition 5C... Approaching part 50... Closest position 6... Air layer 7... Electrode window 8... Positioning recess 9... Outer peripheral wall 10... Thermal insulation layer 11... Exterior case 11A... Body case 11B... Lid case

Claims (8)

A plurality of rechargeable batteries, a battery holder in which each battery is placed in a fixed position, and a metal plate bus bar fixed to the electrode terminals of the battery,
The bus bar has a plurality of fixed terminals connected to the electrode terminals of the battery, a base portion, and a fuse link having a tip connected to the fixed terminal and a root portion connected to the base portion. Then
Further, the base portion has a fuse link connecting portion formed by connecting the base portions of the fuse links, and the fuse link connecting portion is provided with a first fitting portion.
The battery holder has a second fitting part that is connected to the first fitting part and is connected to the fuse link connecting part,
The battery pack, wherein the second fitting part is connected to the first fitting part, and the fuse link connecting part is connected to the battery holder. The battery pack according to claim 1, wherein
A battery pack, wherein the first fitting portion is a fitting hole, and the second fitting portion is a connecting rib formed integrally with the battery holder. The battery pack according to claim 1 or 2, wherein
A battery pack, wherein a first fitting portion provided in the fuse link connecting portion is arranged in the vicinity of a root portion of the fuse link. The battery pack according to claim 3, wherein
The battery pack, wherein the distance (k) between the first fitting portion and the root portion of the fuse link is 5 times or less the lateral width (W) of the fuse link. The battery pack according to any one of claims 1 to 4,
The battery pack, wherein the first fitting portion is provided in the fuse link connecting portion located between the adjacent fixed terminals. The battery pack according to any one of claims 1 to 5, wherein
The battery pack, wherein the first fitting portion is the fuse link connecting portion and is arranged on an extension line of a root portion of the fuse link. The battery pack according to any one of claims 1 to 6, comprising:
The battery holder has an electrode window exposing the electrode terminals of the battery housed in a fixed position,
Further, the battery holder has a supporting surface at a position facing the inner surface of the fuse link,
A battery pack, wherein the fuse link is arranged in contact with or close to the supporting surface. The battery pack according to claim 7, wherein
A battery pack, wherein the electrode window has a quadrangular shape, and the supporting surface is arranged outside an opening edge of the electrode window.

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