Battery pack

Abstract

According to the present invention, adverse effects from high-temperature discharge gas expelled from a discharge valve of a battery cell are suppressed.　In this battery pack, an exterior case (9) accommodates a core pack (20) formed by connecting a plurality of battery blocks (10) in which a plurality of battery cells (1) having a discharge valve have been positioned in fixed locations in a battery holder (2). The battery block (10) comprises an exhaust passage (24) that passes through the battery holder (2). The core pack (20) has a discharge-valve-side end surface positioned at a first end section (20a), and is provided with a partition section (6) between interconnected battery blocks (10). The partition section (6) has a through-hole (6x) open at a location facing the exhaust passage (24). Furthermore, in the core pack (20): the exhaust passage (24) formed on each battery block (10) and the through-hole (6x) formed in the partition section (6) are positioned on the same straight line, forming a discharge-gas exhaust duct (7); and after the discharge gas discharged from the discharge-valve-side end surface positioned on the first end section (20a) has passed through the exhaust duct (7), the discharge gas is exhausted to the exterior from an exhaust section (15).

Description

[Technical field]

[0001] The present invention relates to a battery pack containing multiple battery cells, and more particularly to a battery pack in which multiple battery cells are arranged in fixed positions using a battery holder to form a battery block, and the multiple battery blocks are further connected in series or parallel to achieve high capacity. [Background technology]

[0002] Battery packs, each containing multiple battery cells housed in a case, are used as power sources for portable cordless electrical devices. These battery packs have multiple battery cells connected in series or parallel to increase capacity. In recent years, there has been an increasing demand for higher output from battery packs used as power sources for electrical devices, and non-aqueous electrolyte secondary batteries such as lithium-ion batteries, which have excellent efficiency per unit volume, have been adopted.

[0003] Lithium-ion batteries have high output, but their internal pressure can rise for some reason. To ensure safety against an increase in the battery's internal pressure, a discharge valve is provided that opens at a set pressure to prevent the battery from bursting. When the discharge valve opens, the battery is in an abnormally heated state and high-temperature gas is forcefully ejected from the discharge valve. A battery pack has been developed that has a hole in the exterior case to allow the exhaust gas discharged from the discharge valve to be discharged to the outside. (See Patent Document 1) Furthermore, a battery pack has also been developed in which the exterior case is provided with multiple through holes to improve internal ventilation, promote heat dissipation from the battery, and prevent heat from building up inside the case (see Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2001-196039 A [Patent Document 2] Japanese Patent Application Publication No. 10-162795 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional battery packs have holes in the exterior case to allow exhaust gases sprayed from the exhaust valve to be discharged to the outside. With this type of battery pack, it is difficult to safely discharge the high-temperature exhaust gases that are sprayed forcefully from the battery cells. In particular, the exhaust gases sprayed from the exhaust valve of lithium-ion batteries, which are non-aqueous electrolyte secondary batteries, are abnormally hot at over 400°C and are sprayed forcefully, causing the exhaust gas to melt the exterior case. If the high-temperature exhaust gas is sprayed outside the case and ignites, safety is significantly compromised.

[0006] The present invention was developed with the aim of preventing the above-mentioned problems, and its main object is to provide a battery pack that prevents a decrease in safety due to high-temperature exhaust gas being sprayed from an opening exhaust valve. [Means for solving the problem]

[0007] A battery pack according to one embodiment of the present invention comprises a plurality of battery blocks each formed by arranging a plurality of battery cells in fixed positions in a battery holder, the battery blocks each having a vent valve that opens when the internal pressure exceeds a set pressure, and an exterior case housing a core pack formed by connecting the plurality of battery blocks in the axial direction of the battery cells. The exterior case has an exhaust section that exhausts exhaust gas discharged from the vent valve to the outside. The battery block has an exhaust passage that penetrates the battery holder and extends in the longitudinal direction of the battery cells. The core pack has an exhaust valve side end face on which the vent valve of the battery cell is provided at a first end, and has a partition wall portion between the connected battery blocks that insulates opposing battery cells from each other. The partition wall portion has a through hole opened at a position facing the exhaust passage provided in the battery holder. Furthermore, in a state in which multiple battery blocks are connected to each other, the exhaust passages formed in each battery block and the through holes formed in the partition section are arranged in the same straight line to form an exhaust duct for exhaust gas, and the exhaust gas discharged from the exhaust valve side end face arranged at the first end of the core pack passes through the exhaust duct and is then exhausted to the outside from the exhaust section. Effect of the Invention

[0008] The battery pack of the present invention can enhance safety by suppressing adverse effects caused by high-temperature exhaust gas ejected from the exhaust valve of the battery cell. [Brief description of the drawings]

[0009] [Figure 1] 1 is a perspective view of a battery pack according to an embodiment of the present invention; [Diagram 2] 2 is a vertical cross-sectional view of the battery pack shown in FIG. 1. [Diagram 3] 2 is a vertical cross-sectional view of the battery pack shown in FIG. 1. [Figure 4] FIG. 2 is an exploded perspective view of the battery pack shown in FIG. [Diagram 5] 5 is an exploded perspective view of a core pack of the battery pack shown in FIG. 4. [Figure 6] FIG. 6 is an exploded perspective view of the battery block shown in FIG. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A battery pack according to a first embodiment of the present invention is a battery pack comprising a plurality of battery blocks each formed by arranging a plurality of battery cells in fixed positions in a battery holder, the battery blocks having exhaust valves that open when the internal pressure exceeds a set pressure, and an exterior case housing a core pack formed by connecting the plurality of battery blocks in the axial direction of the battery cells, the exterior case having an exhaust section that exhausts exhaust gas discharged from the exhaust valve to the outside, the battery block having an exhaust passage that passes through the battery holder and extends in the longitudinal direction of the battery cells, and the core pack having an exhaust valve side end face at a first end where the exhaust valve for the battery cell is provided. and a partition wall portion is provided between the battery blocks which are connected to each other to insulate opposing battery cells, and the partition wall portion has a through hole opened at a position opposite the exhaust passage provided in the battery holder. Furthermore, when the core pack is in a state where the multiple battery blocks are connected, the exhaust passages formed in each battery block and the through hole formed in the partition wall portion are arranged on the same straight line to form an exhaust duct for exhaust gas, and the exhaust gas exhausted from the exhaust valve side end face arranged at the first end of the core pack passes through the exhaust duct and is then exhausted to the outside from the exhaust portion.

[0011] The battery pack described above can eliminate the adverse effects of high-temperature exhaust gas ejected from an open exhaust valve, ensuring high safety. This is because the battery pack causes the high-temperature exhaust gas ejected from the exhaust valve to pass through an exhaust duct formed by an exhaust passage penetrating the battery holder and a through hole formed in the partition, and then exhausts the gas to the outside from an exhaust section provided in the exterior case. In particular, the exhaust duct is formed by linearly connecting multiple exhaust passages that open in the longitudinal direction of the battery holder, so that the entire exhaust duct can efficiently cool the high-temperature exhaust gas passing through it as a long flow path. Therefore, the battery pack causes the high-temperature, high-energy exhaust gas ejected from the exhaust valve to pass through the exhaust duct, ideally cooling it and effectively attenuating the thermal energy, thereby eliminating the adverse effects of high-temperature exhaust gas.

[0012] The battery pack of the second embodiment of the present invention further includes a heat-resistant cap connected to a first end of the core pack, the heat-resistant cap including a closing plate portion arranged opposite the end face of the battery block, and a peripheral wall portion connected to the periphery of the closing plate portion and connected to the outer peripheral surface of the battery block, so that exhaust gas discharged from the exhaust valve of the battery cell at the first end collides with the closing plate portion, is changed direction, and flows into the exhaust duct.

[0013] In the battery pack described above, the high-temperature, high-energy exhaust gas injected from the exhaust valve is made to collide with the closing plate of the heat-resistant cap to attenuate its energy, and the exhaust gas with attenuated energy is redirected to pass through the exhaust duct, so that the energy of the exhaust gas discharged from the exhaust valve can be efficiently reduced. In addition, the heat-resistant cap connects the peripheral wall provided along the periphery of the closing plate to the outer circumferential surface of the battery block, so that the exhaust gas injected from the exhaust valve is effectively prevented from leaking outside the heat-resistant cap, and can be efficiently allowed to flow into the exhaust duct.

[0014] In a battery pack according to a third embodiment of the present invention, the heat-resistant cap is made of reinforced plastic that is reinforced by embedding an inorganic material in the resin.

[0015] With the above configuration, the heat resistance of the heat-resistant cap can be improved, thereby effectively preventing the heat-resistant cap from melting due to the high-temperature exhaust gas discharged from the exhaust valve of the battery cell, and effectively preventing the outer casing of the battery pack from melting and causing high-temperature exhaust gas to be discharged to the outside.

[0016] In a battery pack of a fourth embodiment of the present invention, a battery holder is provided with a plurality of retaining tubes that hold battery cells, the plurality of retaining tubes are arranged in multiple rows and columns, partition walls are provided in a crossed position between the retaining tubes, and an exhaust passage is provided in the center of the partition wall.

[0017] According to the above configuration, the battery holder is structured so that multiple holding tubes that hold battery cells are arranged in multiple rows and columns, and an exhaust passage is formed in the center of the partition wall that is formed in an intersecting position between these holding tubes.This makes it possible to form an exhaust passage in the center of the battery holder while maintaining a structure that holds multiple battery cells in a fixed position in a parallel position.

[0018] A battery pack according to a fifth embodiment of the present invention has a battery holder in which four battery cells, which are cylindrical batteries, are arranged in two rows and two columns. A cross-shaped partition wall is provided between the retaining cylinders arranged above, below, left, and right, and an exhaust passage is provided in the center of the partition wall.

[0019] With the above configuration, the four cylindrical batteries are placed in fixed positions, and an exhaust passage is provided in the center of the cross-shaped partition wall formed between the four battery cells, making it possible to provide an exhaust passage with a large opening area by utilizing the dead space between the cylindrical batteries. By providing an exhaust passage with a large opening area in this way, exhaust gas can flow in smoothly and be cooled efficiently.

[0020] In a battery pack according to a sixth embodiment of the present invention, the cross section of the exhaust passage of the battery holder is rectangular, and the four corners of the rectangular exhaust passage are brought close to the holding cylinder.

[0021] According to the above configuration, the cross-sectional shape of the exhaust passage is rectangular with the four corners being close to the retaining cylinder, thereby reducing the effect on the surrounding battery cells of the heat of the high-temperature exhaust gas flowing into the exhaust passage.

[0022] In a seventh embodiment of the battery pack of the present invention, the outer case is provided with a surface plate portion facing the core pack, and an expansion gap for exhaust gas is formed between the surface plate portion and the core pack, and exhaust gas that has passed through the exhaust duct is passed through the expansion gap and exhausted to the outside from the exhaust portion.

[0023] According to the above configuration, the exhaust gas that has passed through the exhaust duct is passed through an expansion gap formed between the core pack and the surface plate portion of the outer case and exhausted to the outside from the exhaust section, so that the exhaust gas whose energy has been attenuated by passing through the exhaust duct can have its energy further attenuated in the expansion gap before being exhausted to the outside.

[0024] In a battery pack according to an eighth embodiment of the present invention, the exterior case is provided with an exhaust section in the surface plate section at the end opposite to the first end of the core pack.

[0025] With the above configuration, the exhaust section is provided on the surface plate at the end of the exterior case facing the first end of the core pack, and the energy of the exhaust gas discharged from the exhaust section can be reliably attenuated. With this structure, the first end of the core pack, where the exhaust valves of the battery cells are located, and the exhaust section provided on the surface plate are located close to each other, and the exhaust gas is diverted to the exhaust duct, lengthening the exhaust path and reliably discharging the energy while attenuating it.

[0026] In a battery pack according to a ninth embodiment of the present invention, the battery cells are cylindrical batteries, and the end faces of multiple cylindrical batteries are arranged on the same plane and in a parallel position in a battery holder to form a battery block.

[0027] A battery pack according to a tenth embodiment of the present invention has battery cells that are non-aqueous electrolyte secondary batteries, and a battery pack according to an eleventh embodiment of the present invention has battery cells that are lithium ion batteries.

[0028] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. In the following description, terms indicating specific directions or positions (e.g., "upper", "lower", and other terms including these terms) are used as necessary, but the use of these terms is for the purpose of facilitating understanding of the invention with reference to the drawings, and the meaning of these terms does not limit the technical scope of the present invention. In addition, parts with the same reference numerals appearing in multiple drawings indicate the same or equivalent parts or members.

[0029] Furthermore, the embodiments shown below are specific examples of the technical ideas of the present invention, and do not limit the present invention to the following. Furthermore, the dimensions, materials, shapes, relative positions, etc. of the components described below are intended to be illustrative and not to limit the scope of the present invention, unless otherwise specified. Furthermore, the contents described in one embodiment or example can be applied to other embodiments or examples. Furthermore, the sizes and positional relationships of the components shown in the drawings may be exaggerated to clarify the explanation.

[0030] A battery pack according to one embodiment of the present invention is shown in Fig. 1 to Fig. 6. Fig. 1 shows a perspective view of the battery pack, Fig. 2 shows a vertical longitudinal sectional view of the battery pack, Fig. 3 shows a vertical transverse sectional view of the battery pack, Fig. 4 shows an exploded perspective view of the battery pack, Fig. 5 shows an exploded perspective view of a core pack of the battery pack, and Fig. 6 shows an exploded perspective view of a battery block.

[0031] 1 to 6 includes a plurality of battery blocks 10 each having a plurality of battery cells 1 arranged in fixed positions by a battery holder 2, and an exterior case 9 housing a core pack 20 formed by connecting the plurality of battery blocks 10 in the axial direction of the battery cells 1. The core pack 20 shown in the figures further includes a heat-resistant cap 5 connected to the first end 20a, a partition wall 6 disposed between the mutually connected battery blocks 10 to insulate the opposing battery cells 1 from each other, and a circuit board 4 disposed along the first surface 10A of the battery block 10 and connected to the battery block 10.

[0032] The battery pack 100 is used, for example, as a power source for a portable electrical device such as a vacuum cleaner. However, the present invention does not specify the electrical device for which the battery pack is intended, and the battery pack can also be used as a power source for other electrical devices, such as power tools and assisted bicycles. The battery pack can be structured to be detachably connected to the electrical device, or can be built into the electrical device in a non-detachable state.

[0033] (Battery cell 1) Battery cell 1 is a cylindrical battery with an exhaust valve on end face 1a that opens when the internal pressure exceeds a set pressure. A cylindrical battery contains electrodes and electrolyte in a cylindrical metal case. The metal case has a sealed structure with a sealing plate hermetically fixed to the opening of a cylindrical exterior can that closes the bottom. The exterior can is manufactured by pressing a metal plate into a cylindrical shape. The sealing plate is hermetically fixed by crimping to the periphery of the opening of the exterior can via an insulating packing.

[0034] Although not shown, the battery cell 1 is provided with a discharge valve on the sealing plate to prevent the internal pressure of the metal case from becoming abnormally high and causing damage. The battery cell 1 has an opening for the discharge valve on the sealing plate, which opens to discharge internal gases and the like. However, the battery cell 1 can also have a discharge valve and its opening on the bottom of the exterior can. The discharge valve opens when the internal pressure exceeds a set pressure, for example, 1.5 MPa, to prevent the metal case from being destroyed by the internal pressure rise. The discharge valve opens under abnormal conditions. Therefore, when the discharge valve is open, the temperature of the battery cell 1 is also very high. Therefore, the gas and electrolyte (ejected material) discharged from the open discharge valve are abnormally high. In particular, a battery pack in which the battery cell 1 is a non-aqueous electrolyte secondary battery such as a lithium ion battery will discharge gas at an abnormally high temperature of 400°C or higher. Furthermore, since the lithium ion battery is filled with a non-aqueous electrolyte, if this is discharged to the outside of the case at a high temperature, it may come into contact with air and ignite, causing the temperature to become even higher. Not only in lithium-ion batteries, but also in other rechargeable batteries, the exhaust gas ejected from the open exhaust valve becomes very hot, so it is important to attenuate the energy of the exhaust gas and exhaust it outside the case to increase safety.

[0035] (Battery block 10) As shown in FIG. 6, a battery block 10 has multiple battery cells 1 arranged in parallel via a plastic battery holder 2. The battery block 10 in the figure has four battery cells 1 arranged in two rows and two columns in the battery holder 2. The battery block 10 in the figure has four battery cells 1 arranged in two rows and two columns, with each battery cell 1 connected in series with a lead plate 3. The battery block 10 in the figure has four battery cells 1 arranged in two rows and two columns and connected in series, but the number of battery cells 1 and the connection form can be freely changed. Each battery block 10 can be made common by arranging battery cells 1 of the same external shape, for example cylindrical batteries of the same dimensions, in fixed positions in battery holders 2 of the same shape and connecting the battery cells 1 with lead plates 3 of the same shape. Battery blocks 10 in which all parts are common can be mass-produced particularly cheaply.

[0036] (Battery holder 2) The battery holder 2 in Figures 5 and 6 arranges multiple battery cells 1 in a parallel position with the terminal surfaces at both ends on the same plane. The battery holder 2 arranges multiple battery cells 1 in multiple rows and columns. The battery holder 2 in the figures is made by molding plastic into a shape with a retaining cylinder 22 that holds four battery cells 1 in fixed positions. This battery holder 2 is shaped so that four sets of retaining cylinders 22 are connected in two rows and two columns in a parallel position, and the inside of the retaining cylinders 22 is made to be roughly the same shape as the outer shape of the battery cells 1 to form the retaining section 21.

[0037] In the battery block 10 of FIG. 6, the battery holder 2 is divided in the longitudinal direction of the battery cell 1 into a first battery holder 2A and a second battery holder 2B. The long and thin battery cell 1 can be smoothly inserted into this battery holder 2. The first battery holder 2A and the second battery holder 2B are separately manufactured by molding plastic, and are connected to each other by inserting the battery cell 1. The first battery holder 2A and the second battery holder 2B are provided with a cylindrical holding cylinder 22 so that the cylindrical battery cell 1 can be inserted and positioned in a fixed position. The inner shape of the holding cylinder 22 is almost the same as the outer shape of the battery cell 1, and more precisely, it is slightly larger so that the battery cell 1 can be smoothly inserted and positioned in a fixed position. The first battery holder 2A and the second battery holder 2B of this structure are connected to each other in a fixed position via the battery cell 1 with both ends of the cylindrical battery cell 1 inserted. The first battery holder 2A and second battery holder 2B can be connected more accurately by fitting their opposing surfaces together, and are connected in fixed positions via a non-melting plate (described below). The first battery holder 2A and second battery holder 2B, which are connected via the battery cell 1, are connected to a circuit board 4 and maintained in a connected state.

[0038] The battery block 10 shown in Figures 3 and 6 has retaining tubes 22 arranged between adjacent battery cells 1 as partition walls 23, and a non-molten plate 13, such as a mica plate, arranged inside the partition walls 23. The battery holder 2 shown in the figures arranges the battery cells 1 in two rows and two columns, so a cross-shaped partition wall 23 is provided between four sets of battery cells 1 arranged vertically and horizontally. The partition wall 23 has insertion gaps 25 into which the internal non-molten plate 13 is inserted. The partition wall 23 inserts the non-molten plate 13, such as a mica plate, into this insertion gap 25. This battery block 10 can prevent thermal runaway from being induced in an adjacent battery cell 1 when one of the battery cells 1 experiences thermal runaway and generates abnormal heat.

[0039] (Exhaust passage 24) Furthermore, the battery block 10 is provided with an exhaust passage 24 that passes through the battery holder 2 and extends in the longitudinal direction of the battery cells 1. The battery holder 2 is provided with multiple holding tubes 22 that hold the battery cells 1, and the multiple holding tubes 22 are arranged in multiple rows and columns, with partition walls 23 that are in a cross-shaped position between the holding tubes 22, and an exhaust passage 24 is provided in the center of the partition walls 23. The battery holder 2 shown in Figures 3 and 6 has cylindrical holding tubes 22 that store cylindrical batteries arranged in multiple rows and columns, in two rows and two columns as shown in the figures, with cross-shaped partition walls 23 provided between the holding tubes 22 arranged above, below, left and right, and an exhaust passage 24 provided in the center of this cross-shaped partition wall 23. This structure has the characteristic of making effective use of the dead space that occurs between cylindrical batteries to increase the opening area of ​​the exhaust passage 24. The large volume of this exhaust passage 24 allows exhaust gas discharged from the exhaust valve of the battery cells 1 to flow in smoothly.

[0040] The exhaust passage 24 shown in Fig. 3 is provided in the center of the cross-shaped partition wall 23 as a square prism-shaped through hole extending in the longitudinal direction of the battery cell 1. In the battery holder 2, the cross section of the exhaust passage 24 is square, with the four corners of the square-shaped exhaust passage 24 being close to the retaining cylinder 22. With this structure, the cross section of the exhaust passage 24 is square with the four corners being close to the retaining cylinder 22, which reduces the effect on the battery cell 2 of the heat of the high-temperature exhaust gas that flows into the exhaust passage 24. However, the cross section of the exhaust passage is not limited to a square, and can also be circular, elliptical, polygonal, etc.

[0041] (Partition wall 6) The partition wall 6 is disposed between the battery blocks 10 arranged side by side in the longitudinal direction. The core pack 20 shown in FIG. 5 has two battery blocks 10 connected in a straight line, and a partition wall 6 is disposed between the opposing battery blocks 10 to insulate them from each other. The partition wall 6 is produced by molding a material with excellent insulating and heat-insulating properties, such as PBT resin, which is a fiber-reinforced plastic reinforced by embedding inorganic fibers such as glass fibers. The partition wall 6 shown in the figure includes an insulating plate portion 6X that insulates the opposing battery cells 1 from each other, and a peripheral wall portion 6B that is connected to the periphery of the insulating plate portion 6X and is connected to the outer circumferential surface of the battery block. The partition wall 6 is connected to a fixed position of the battery block 10 by disposing the peripheral wall portion 6B along the outer circumferential surfaces of the battery blocks 10 arranged on both sides of the insulating plate portion 6X.

[0042] Furthermore, the partition 6 shown in the figure has a through hole 6x opened in the center of the insulating plate portion 6X. This through hole 6x is provided in a position facing an exhaust passage provided in the battery block 10 arranged adjacent to the partition. Since the exhaust passage 24 shown in the figure is rectangular, the through hole 6x in the partition 6 is also rectangular and opens to a size approximately equal to that of the exhaust passage 24.

[0043] In the above core pack 20, multiple battery blocks 10 are aligned in the longitudinal direction and connected in a straight line, and the exhaust passages 24 formed in each battery block 10 and the through holes 6x formed in the partition wall 6 are arranged on the same straight line to form an exhaust duct 7 for exhaust gas. This exhaust duct 7 is formed to penetrate the core pack 20 in the axial direction, and is structured to pass exhaust gas discharged from the exhaust valve side end face 1a arranged at the first end 20a, thereby attenuating energy. In this way, the exhaust duct 7 formed by connecting multiple exhaust passages 24 formed to penetrate the battery blocks 10 in the longitudinal direction can have a long overall length, and the exhaust gas passing through the inside of the exhaust duct 7 can be effectively cooled.

[0044] (Heat-resistant cap 5) In the battery pack 100 shown in Figs. 2 to 5, a heat-resistant cap 5 is connected to an end of the core pack 20 in order to attenuate and exhaust the energy of exhaust gas ejected from the exhaust valve of the battery cell 1 arranged at the first end 20a of the core pack 20. The heat-resistant cap 5 is made by molding a thermoplastic plastic with better heat resistance than the battery holder 2 and the exterior case 9. Plastic with excellent heat resistance is made by molding a fiber-reinforced plastic such as PBT resin reinforced with inorganic fibers such as glass fiber. The heat-resistant cap 5 is connected to the end of the battery block 10 to attenuate the energy of exhaust gas ejected from the valve-side end face of the battery cell 1 and change the flow direction. The heat-resistant cap 5 includes a closing plate portion 5X arranged opposite the end face 10X of the battery block 10 and peripheral wall portions 5A, 5B, and 5C connected to the periphery of the closing plate portion 5X, and the closing plate portion 5X and the peripheral wall portions 5A, 5B, and 5C are molded into an integral structure.

[0045] The closing plate portion 5X has an exhaust gap 11 between it and the end face 10X of the battery block 10 to allow the exhaust gas ejected from the exhaust valve to flow efficiently into the exhaust duct 7. The exhaust gap 11 allows the exhaust gas ejected from the exhaust valve to collide with the inner surface of the closing plate portion 5X to attenuate its energy. The exhaust gap 11, which is provided between the closing plate portion 5X and the end face 10X of the battery block 10, or more precisely, between the closing plate portion 5X and the end face 1a of the battery cell 1, is set to, for example, 0.5 mm or more and 3 mm or less so that the exhaust gas can be smoothly exhausted while attenuating the kinetic energy of the exhaust gas. A lead plate 3 fixed to the battery cell 1 is placed in the exhaust gap 11.

[0046] The exhaust gas injected into the discharge gap 11 has its momentum weakened by the closing plate portion 5X and flows into the exhaust passage 24. The heat-resistant cap 5 changes the direction of the exhaust gas injected into the discharge gap 11 and causes it to flow into the exhaust passage 24. The heat-resistant cap 5 causes the exhaust gas injected into the discharge gap 11 to collide with the closing plate portion 5X to attenuate its energy, and then changes the flow direction and causes the gas to flow into the exhaust passage 24 without being scattered to the surroundings.

[0047] 3 and 5 includes peripheral wall portions 5A, 5B, and 5C that are connected to the periphery of the closing plate portion 5X and connected to the outer peripheral surface of the battery block 10. The heat-resistant cap shown in the figures includes a peripheral wall portion 5A that faces the first surface 10A (top surface in the figures), a peripheral wall portion 5B that is connected to the second surface 10B (both side surfaces in the figures), and a peripheral wall portion 5C that is connected to the third surface 10C (bottom surface in the figures). The heat-resistant cap 5 is connected to a fixed position at the end of the battery block 10 with the peripheral wall portions 5A, 5B, and 5C in close contact with the outer peripheral surface of the battery block 10. In this way, the heat-resistant cap 5 that includes the peripheral wall portions 5A, 5B, and C that are connected in contact with the outer peripheral surface of the battery block 10 can prevent the exhaust gas injected into the exhaust gap 11 from leaking around the battery block 10 and can reliably guide the exhaust gas to the exhaust passage 24.

[0048] (Lead plate 3) The battery cells 1 in the battery block 10 are electrically connected in series via lead plates 3. The lead plates 3 are made by bending a metal plate with excellent conductivity. The lead plates 3 are fixed by welding to electrodes provided on the end faces of the battery cells 1. In the battery block 10 shown in FIG. 6, the individual battery cells 1 are connected in series via the lead plates 3 to increase the output voltage, but the battery block 10 can also connect the battery cells 1 in parallel via the lead plates 3, or in series and parallel. The lead plates 3 to which the battery cells 1 are connected are connected to a circuit board 4.

[0049] (Circuit board 4) The circuit board 4 is equipped with a protection circuit that charges and discharges the battery cells 1, and connects each battery cell 1 to the protection circuit. The protection circuit detects the voltage and current of each battery cell 1 and controls the charging and discharging current to charge and discharge while protecting the battery. The circuit board 4 can also connect output lead parts 3x for inputting the positive and negative outputs of each battery block 10, or intermediate potential lead parts 3y for measuring an intermediate potential in order to grasp the voltage of each battery cell 1, or the potential of a temperature detection part (not shown) for detecting the temperature of each battery cell 1. A thermistor or the like is used as the temperature detection part.

[0050] The circuit board 4 is disposed along the first surface 10A (the upper surface in the figure) adjacent to the end surface 10X of the battery block 10 on which the heat-resistant cap 5 is disposed. The circuit board 4 is disposed so as to form a gap between the circuit board 4 and the first surface 10A of the battery block 10.

[0051] The circuit board 4 is connected to a fixed position on the first surface 10A of the battery block 10. The battery holder 2 shown in the perspective view of FIG. 6 has mating protrusions 29 protruding from the surface facing the circuit board 4 (the upper surface in the figure) in order to connect the circuit board 4 to a fixed position. The mating protrusions 29 are hollow columnar bosses that protrude vertically upward from the four corners of the facing surface, and are molded integrally with the plastic of the battery holder 2. As shown in FIG. 4, the mating protrusions 29 guide the mating recesses 4a provided in the circuit board 4 to position the circuit board 4 in a fixed position. Furthermore, the battery holder 2 shown in FIG. 6 has mounting ribs 31 molded integrally at multiple locations on the facing surface for placing the circuit board 4 thereon to determine the up-down position. The mounting ribs 31 are provided at multiple locations on both sides of the facing surface of the battery holder 2, and position the circuit board 4 in a fixed position at a specified interval from the first surface 10A. Furthermore, the battery block 10 in FIG. 6 is provided with a locking hook 30 for the circuit board 4, which is molded integrally with the surface facing the battery holder 2. As shown in FIG. 4, the locking hook 30 locks the circuit board 4 arranged on the first surface 10A, and places it in a fixed position. The output lead portion 3x and the intermediate potential lead portion 3y protruding from the first surface 10A of the battery block 10 are inserted into the through holes of the circuit board 4, the fitting convex portion 29 of the battery holder 2 is guided into the fitting concave portion 4a, and the bottom surface of the circuit board 4 is placed on the placing rib 31 and placed in a fixed position, and then the circuit board 4 is locked in place by being locked by the locking hook 30. With the circuit board 4 set in a fixed position by the locking hook 30, the output lead portion 3x and the intermediate potential lead portion 3y are soldered to the connection portion of the circuit board 4 to connect the battery block 10.

[0052] Furthermore, the circuit board 4 shown in the figure connects multiple battery blocks 10, electrically connecting and further physically connecting each battery block 10. The battery pack 100 shown in the exploded oblique view of Figure 5 connects the multiple battery blocks 10 even more firmly by screwing the circuit board 4 to two sets of battery blocks 10 with set screws 18 that penetrate the circuit board 4. The battery block 10 has fixing bosses 28, into which the set screws 18 are screwed, on the surface facing the battery holder 2.

[0053] The output lead portions 3x of the battery blocks 10 are connected via a circuit board 4, and further connected to a connector 19. The circuit board 4 has a conductive layer (not shown) such as copper foil on its surface. The conductive layer electrically connects the connection portions of the output lead portions 3x to connect the battery blocks 10 in series, and also connects the output lead portions 3x to lead wires 16 of the connector 19. The conductive layer also connects the connection portion of the intermediate potential lead portion 3y to a protection circuit of the circuit board 4.

[0054] As described above, multiple battery blocks 10 are connected in a linear fashion and fixed to the circuit board 4 to form a battery core pack 20. The core pack 20 shown in the figure has two battery blocks 10 connected in a linear fashion, with a partition wall 6 disposed between the opposing battery blocks 10 to insulate them from each other, heat-resistant caps 5 connected to both ends, and a circuit board 4 connected to a first surface 10A of the battery blocks 10.

[0055] (Outer case 9) The exterior case 9 is formed in a rectangular cylindrical box shape as shown in Figs. 1 to 4. The exterior case 9 in the figures is divided into a case main body 9A and a closing portion 9B. As shown in Fig. 3, the exterior case 9 houses a battery core pack 20 including two battery blocks 10, a heat-resistant cap 5, a partition wall portion 6, and a circuit board 4. The exterior case 9 extends a connector 19 to the outside for connecting to an electrical device to which power is supplied by the battery pack 100. The exterior case 9 is made of a material with excellent insulating and heat-insulating properties, such as polycarbonate or ABS, or a resin that combines these.

[0056] The above-mentioned exterior case 9 has an exhaust section 15 that exhausts the exhaust gas discharged from the exhaust valve to the outside. In the exterior case 9 shown in the figure, the exhaust section 15 is an end of the case body 9A, where the connector 19 is drawn out of the case. This exterior case 9 has a structure in which an opening window 9a is provided in the case body 9, and the lead wire 16 is guided into a groove 9b provided in the opening edge of the opening window 9a to draw the connector 19 out of the case. Therefore, in this exterior case, the opening window 9a and the groove 9b through which the lead wire is drawn out serve as an exhaust section for exhausting the exhaust gas in the case to the outside. In this exterior case 9, the connector 19 is passed through the opening window 9a opened in the case body 9A, the battery core pack 20 is stored in the case body 9A, and then the case body 9A is closed with the lid 9B, the lead wire 16 is passed through the groove 9b provided in the peripheral portion of the opening window 9a, and then the opening window 9a of the case body 9A is closed with the closing lid 17.

[0057] Furthermore, the exterior case 9 shown in Fig. 2 has a surface plate portion 9x in which the case body 9A faces the battery core pack 20. When the exterior case 9 houses the battery core pack 20 inside, an expansion gap 14 for exhaust gas is formed between the circuit board 4 and the surface plate portion 9x. This battery pack 100 passes the exhaust gas that has passed through the exhaust duct 7 through the expansion gap 14 and exhausts it to the outside from the exhaust section 15. In this way, with a structure in which the exhaust gas that has passed through the exhaust duct 7 passes through the expansion gap 14 and exhausts it to the outside from the exhaust section 15, the exhaust gas whose energy has been attenuated in the exhaust duct 7 can be further attenuated in the expansion gap 14 and exhausted to the outside.

[0058] Furthermore, the exterior case 9 shown in FIG. 2 has an exhaust section 15 on the surface plate section 9x at the end opposite the first end section 20a of the core pack 20. The battery pack 100 having the above structure can reliably attenuate the energy of the exhaust gas discharged from the exhaust section 15 while being structured to provide the exhaust section 15 on the surface plate section 9x at the end of the exterior case 9 opposite the first end section 20a of the core pack 20. This structure can reliably attenuate and discharge the energy of the exhaust gas by diverting it to the exhaust passage 24 while arranging the first end section 20a of the core pack 20, where the exhaust valve of the battery cell 1 is arranged, close to the exhaust section 15 provided on the surface plate section 9x. Therefore, even though the linear distance between the exhaust valve of the battery cell 1 and the exhaust section 15 of the exterior case 9 is shortened, the path of the exhaust gas can be lengthened to reliably attenuate the energy.

[0059] In the exterior case shown in Fig. 2, the exhaust section 15 is provided at an end of the surface plate section 9x of the case body 9A, which is on the same side as the first end section 20a provided on the core pack 20, but the exhaust section 15 may be provided in the center or on the side of the surface plate section 9x of the case body 9A. Even in this case, the exhaust gas discharged from the exhaust valve side end face 1a of the battery cell 1 arranged at the first end section 20a of the core pack 20 passes through the exhaust duct 7 from the exhaust gap 11, as shown by the arrows in Figs. 2 and 3, and then passes through the expansion gap 14 from the exhaust duct 7, before being discharged to the outside from the exhaust section 15. In this way, the battery pack of the present invention can lengthen the path of the exhaust gas by passing the high-temperature exhaust gas through the exhaust duct 7 formed by penetrating the core pack 20, and can reliably attenuate the energy and discharge it to the outside. Furthermore, in the battery pack 100, even at the exhaust valve side end face of the battery cell arranged in a position other than the first end 20a of the core pack 20, the exhaust gas path can be lengthened, and the energy can be exhausted to the outside while attenuating.

[0060] (Heat dissipation plate 8) Furthermore, the battery pack 100 in Fig. 4 has a heat dissipation plate 8 disposed on the underside of the core pack 20 to more effectively attenuate the energy of exhaust gas. The heat dissipation plate 8 is disposed inside the closing portion 9B of the exterior case 9 and between it and the battery block 10, and attenuates the energy of exhaust gas emitted from the battery cells 1. A plate material with better thermal conductivity than the exterior case 9 is suitable for the heat dissipation plate 8. This heat dissipation plate 8 absorbs the thermal energy of the exhaust gas that it collides with, and quickly diffuses the absorbed thermal energy over a wide area for thermal conduction to the exterior case 9, which then dissipates the thermal energy to the outside over a wide area.

[0061] A metal plate is used for the heat dissipation plate 8 as a plate material with favorable heat conduction properties. In particular, an aluminum (including aluminum alloy) plate is suitable for the heat dissipation plate 8. An aluminum plate has heat resistance, excellent heat conduction properties, and is lightweight, so it can quickly diffuse the thermal energy of the exhaust gas and dissipate heat efficiently while reducing weight. The battery pack 100 in FIG. 4 has a strip shape arranged along the longitudinal direction of the blocking portion 9B, and is bent at both ends into an L-shape and arranged between the heat-resistant cap 5 and the exterior case 9. This covers the case connection parts at both ends of the exterior case 9 from the inside, preventing the exhaust gas discharged from the exhaust valve from being discharged to the outside from these parts. [Industrial Applicability]

[0062] The battery pack of the present invention is suitably used as a power source for portable electrical devices such as vacuum cleaners, power tools, and power-assisted bicycles. [Explanation of symbols]

[0063] 100…Battery pack 1. Battery cell 1a...end face 2…Battery holder 2A…1st battery holder 2B…Second battery holder 3...Lead plate 3x…Output lead 3y...Intermediate potential lead 4…Circuit board 4a…Mating recess 5…Heat-resistant cap 5X…Closing plate section 5A, 5B, 5C...peripheral wall part 6...Partition wall part 6X…Insulating plate part 6B…Peripheral wall part 6x…Through holes 7…Exhaust duct 8…Heat dissipation plate 9…Outer case 9A…Case body 9a…Opening window 9b…Groove 9x…Surface plate section 9B…Occluded part 10…Battery block 10X...end face 10A…First surface 10B…Second surface 10C…Third Surface 11...Discharge gap 13…Non-melting plate 14...Expansion gap 15…Exhaust section 16…Lead wire 17…occlusion lid 18…Set screw 19…Connector 20…Core Pack 20a...first end 21...Holding part 22...Holding cylinder 23…Partition wall 24…Exhaust passage 25…Insertion gap 28...Fixed boss 29…Fitting protrusion 30…Latching hook 31...Ribs

Claims

1. a plurality of battery blocks each including a plurality of battery cells arranged in fixed positions in a battery holder, the battery cells having a discharge valve that opens when the internal pressure exceeds a set pressure; an exterior case that houses a core pack formed by connecting a plurality of the battery blocks in the axial direction of the battery cells; A battery pack comprising: the exterior case has an exhaust part that exhausts the exhaust gas discharged from the exhaust valve to the outside, The battery block includes: an exhaust passage penetrating the battery holder and extending in the longitudinal direction of the battery cell; The core pack comprises: a discharge valve side end surface on which a discharge valve of the battery cell is provided is disposed at a first end portion; a partition wall portion is provided between the battery blocks that are connected to each other, the partition wall insulating opposing battery cells from each other; the partition wall has a through hole formed in a position facing the exhaust passage provided in the battery holder, Furthermore, in the core pack, when the plurality of battery blocks are connected together, an exhaust passage formed in each battery block and a through hole formed in the partition portion are arranged on the same straight line to form an exhaust duct for exhaust gas, A battery pack characterized in that exhaust gas discharged from an exhaust valve side end face arranged at a first end of the core pack passes through the exhaust duct and is then discharged to the outside from the exhaust portion.

2. 2. The battery pack of claim 1, further comprising: a heat resistant cap coupled to a first end of the core pack; The heat-resistant cap is a closing plate portion disposed opposite an end face of the battery block; a peripheral wall portion connected to a periphery of the closing plate portion and connected to an outer peripheral surface of the battery block, a closing plate portion that closes the exhaust duct and changes direction when exhaust gas is discharged from the exhaust valve of the battery cell at the first end portion, and the exhaust gas is then discharged into the exhaust duct.

3. 3. The battery pack according to claim 2, The battery pack according to claim 1, wherein the heat-resistant cap is made of a reinforced plastic material having an inorganic material embedded in the resin for reinforcement.

4. 4. The battery pack according to claim 1, the battery holder includes a plurality of holding cylinders that hold the battery cells, A battery pack comprising: a plurality of the holding cylinders arranged in multiple rows and columns; partition walls arranged in a crossing position between the holding cylinders; and the exhaust passage provided in the center of the partition walls.

5. 5. The battery pack according to claim 4, the battery holder has four battery cells, which are cylindrical batteries, arranged in two rows and two stages, a cross-shaped partition wall is provided between the retaining cylinders arranged above, below, left, and right, and the exhaust passage is provided in the center of the partition wall.

6. 6. The battery pack according to claim 5, The battery pack is characterized in that the cross section of the exhaust passage of the battery holder is rectangular, and the four corners of the rectangular exhaust passage are disposed close to the retaining cylinder.

7. 7. The battery pack according to claim 1, the outer case includes a surface plate portion facing the core pack, and an expansion gap for exhaust gas is formed between the surface plate portion and the core pack, The battery pack is characterized in that exhaust gas that has passed through the exhaust duct passes through the expansion gap and is exhausted to the outside from the exhaust portion.

8. 8. The battery pack according to claim 7, a first end of the core pack and a second end of the core pack, the first end being opposite to the first end of the core pack, the first end being opposite to the first end of the core pack, and the second end being opposite to the first end of the core pack.

9. 9. The battery pack according to claim 1 , a battery block formed by arranging a plurality of cylindrical batteries in the battery holder in a parallel orientation and with the end faces of the cylindrical batteries being flush with one another;

10. 10. The battery pack according to claim 9, The battery pack, wherein the battery cells are lithium ion batteries.

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