JP7423275B2 - battery pack - Google Patents

Description

The present invention relates to a battery pack in which a case houses a battery cell having a discharge valve that opens when the internal pressure becomes higher than a set pressure.

In recent years, battery packs used as power sources for portable electrical devices have been required to have even higher output, and non-aqueous electrolyte secondary batteries such as lithium-ion batteries, which have excellent efficiency per unit volume, are being adopted. . Although lithium ion batteries have high output, internal pressure may increase for some reason. In order to ensure safety against increases in the internal pressure of the battery, a discharge valve is provided that opens at a set pressure to prevent explosion. (See Patent Document 1)

For battery packs with built-in non-aqueous electrolyte secondary batteries such as lithium-ion batteries in the outer case, when the discharge valve is open, the battery is in an abnormal state of heat generation, and high-temperature gas is released from the discharge valve. It squirts often. The high-temperature gas injected from the exhaust valve has high thermal energy and kinetic energy, and can thermally melt and damage the outer case. A damaged exterior case spews out high-temperature gas outside the case, but the gas that is jetted outside can come in contact with the air and ignite. Further, since the flame generated within the outer case is released from the outer case to the outside, safety cannot be further ensured.

International publication WO2011/007533

One object of the present invention is to provide a battery pack that can improve safety by suppressing harmful effects and flames caused by high-temperature exhaust gas injected from a battery discharge valve.

A battery pack according to an aspect of the present invention includes one or more battery cells having electrodes at both ends of a cylindrical outer can and a discharge valve that opens when the internal pressure exceeds a set pressure, and the battery cells are positioned and held. The battery holder includes a battery holder, and a facing plate portion provided on the end face side of the battery cell held by the battery holder so as to be spaced apart from the end face of the battery cell. The battery cell has one electrode as a convex electrode, is provided with a discharge valve inside the convex electrode, and has a gas exhaust port opened on the outer peripheral surface of the convex electrode. The battery holder includes a peripheral wall portion that covers the outer peripheral surface of the end portion of the battery cell, and an end plate portion that faces the end surface of the outer can of the battery cell. The end plate portion disposed on the convex electrode side of the battery cell has an electrode window that exposes the convex electrode, and has an inner shape gradually formed on the inner peripheral surface of the electrode window in the direction away from the end surface of the outer can. It has a tapered surface that is slanted so that it increases.

The battery pack of the present invention can improve safety by suppressing harmful effects and flames caused by high-temperature, high-pressure exhaust gas injected from the discharge valve of the battery.

1 is a vertical sectional view showing a battery pack according to an embodiment of the present invention. FIG. 2 is a perspective view of a battery block built into the battery pack shown in FIG. 1. FIG. 3 is an exploded perspective view of the battery block shown in FIG. 2. FIG. FIG. 2 is an enlarged schematic sectional view of a main part of the battery pack shown in FIG. 1. FIG. FIG. 7 is an enlarged schematic cross-sectional view of a main part of a battery pack according to another embodiment of the present invention. FIG. 7 is an enlarged schematic cross-sectional view of a main part of a battery pack according to another embodiment of the present invention. FIG. 7 is an enlarged schematic cross-sectional view of a main part of a battery pack according to another embodiment of the present invention. FIG. 2 is an enlarged schematic cross-sectional view of main parts of a conventional battery pack.

Embodiments of the present invention may be specified by the following configurations.
The battery pack according to the first embodiment of the present invention has electrodes at both ends of a cylindrical outer can, one or more battery cells equipped with a discharge valve that opens when the internal pressure exceeds a set pressure, and the battery cells are positioned. A battery pack comprising: a battery holder for holding the battery cell as a battery; and a facing plate portion provided on the end face side of the battery cell held in the battery holder so as to be spaced apart from the end face of the battery cell, the battery cell being held on one side. The electrode is a convex electrode, a discharge valve is provided inside the convex electrode, and a gas exhaust port is opened on the outer circumferential surface of the convex electrode, and the battery holder covers the outer circumferential surface of the end of the battery cell. The battery cell includes a peripheral wall portion and an end plate portion facing the end surface of the outer can of the battery cell, and the end plate portion disposed on the convex electrode side of the battery cell has an electrode window that exposes the convex electrode. In addition, the electrode window has a tapered surface on the inner circumferential surface thereof such that the inner diameter thereof gradually increases in the direction away from the end surface of the outer can.

With the above configuration, even if the exhaust valve is opened in the event of an abnormality in the battery cell and high-temperature, high-pressure exhaust gas is released from the gas exhaust port of the convex electrode, the exhausted gas is routed along the tapered surface of the electrode window. By moving the exhaust gas diagonally, it is possible to diffuse the exhaust gas radially and suppress the harmful effects caused by high temperature and high pressure exhaust gas. In particular, it suppresses high-temperature, high-pressure exhaust gas from colliding vertically with the opposing plate facing the tip surface of the convex electrode, and reduces the impact of collision by colliding the exhaust gas diagonally. This provides an advantage in that damage to the opposing plate portion can be suppressed.

In particular, in the above battery pack, the battery holder includes a peripheral wall portion that covers the outer peripheral surface of the end portion of the battery cell, and the protruding electrode is exposed from the electrode window provided in the end plate portion, so that the peripheral wall portion This makes it possible to accurately position and arrange the convex electrode with respect to the electrode window of the end plate portion while holding the battery cell. Therefore, even when high-pressure exhaust gas is vigorously injected from the gas outlet of the convex electrode, the electrode window is reliably prevented from shifting relative to the convex electrode, and the exhaust gas is directed toward the tapered surface. It can be spread while guiding accurately against the target.

Here, consider the case where exhaust gas is released from the exhaust valve in a battery pack as shown in the enlarged cross-sectional view of FIG. In this example, the convex electrode 113 of the battery cell 101 is positioned in the electrode window 123 of the end plate portion 122 using the battery holder 102 that holds the battery cell 101 . In addition, the battery cell 101 is configured such that a discharge valve (not shown) is provided inside the metal convex electrode 113 formed by forming a metal plate into a low columnar shape to exhaust gas from the side surface of the convex electrode 113. A gas exhaust port 116 is opened at the bottom. Further, on the end surface side of the convex electrode 113 of the battery cell 101, a wall surface of the outer case 103 is arranged as a facing plate part 104 at a distance. In this state, when the internal pressure of the battery cell 101 rises and exceeds the set pressure and the exhaust valve is opened, high temperature and high pressure exhaust gas is discharged from the side surface of the convex electrode 113. In this case, since the vertical surface 106, which is the inner circumferential surface of the electrode window 123, is arranged at a position facing the side surface of the convex electrode 113, the exhaust gas discharged from the gas exhaust port 116 is directed to the vertical surface 106. Upon collision, it is bent upward and collides with the opposing plate portion 104. At this time, the high-temperature, high-pressure exhaust gas collides with force in the vertical direction against a narrow area of the opposing plate portion 104, causing significant damage to the opposing plate portion 104, and in some cases, melting the opposing plate portion 104. Exhaust gas is vigorously injected to the outside of the opposing plate portion 104. If high-temperature, high-pressure exhaust gas is injected to the outside of the opposing plate portion 104, for example to the outside of the exterior case 103, without loss of energy, an extremely dangerous situation will result.

On the other hand, in the battery pack of the present invention, as shown in the enlarged cross-sectional view of FIG. A tapered surface 6 is provided whose inner shape gradually increases towards the end. Therefore, when the internal pressure of the battery cell 1 increases and the discharge valve (not shown) is opened, the exhaust gas discharged from the gas discharge port 16 provided on the side surface of the convex electrode 13 is discharged from the opposing plate. It advances along the tapered surface 6 without being bent in the direction of 4. This prevents the high-temperature, high-pressure exhaust gas from colliding vigorously in the vertical direction with respect to the narrow range of the opposing plate portion 4. The exhaust gas traveling along the tapered surface 6 is radially diffused in a plan view, thereby reducing its kinetic energy and thermal energy, and when it collides with the opposing plate portion 4, it collides obliquely. The kinetic energy is dispersed and the vertical kinetic energy is suppressed. Therefore, it is possible to suppress the situation in which the opposing plate portion is damaged or melted by the high-temperature, high-pressure exhaust gas, and to reduce the adverse effects caused by the high-temperature, high-pressure exhaust gas.

The battery pack according to the second embodiment of the present invention further includes an exterior case that accommodates a battery holder that holds battery cells, and the opposing plate portion is a wall surface of the exterior case.

According to the above configuration, the harmful effects of high-temperature and high-pressure exhaust gas on the wall surface of the outer case, which is the opposing plate part, such as damage or melting of the outer case, are suppressed, and the high-temperature and high-pressure exhaust gas is prevented from being damaged or melted. It has the advantage of being able to prevent spraying directly from the vicinity of the end face of the battery cell to the outside of the exterior case.

In the battery pack according to the third embodiment of the present invention, the convex electrode has a columnar shape protruding from the end surface of the outer can, has a plurality of gas exhaust ports opened on the outer peripheral surface of the columnar shape, and has an electrode window. The upper end of the formed tapered surface is made higher than the upper opening edge of the gas discharge port.

According to the above configuration, the exhaust gas injected from the vicinity of the upper opening edge of the gas exhaust port can reliably collide with the tapered surface, and the exhaust gas can be diffused along the tapered surface.

In the battery pack according to the fourth embodiment of the present invention, the convex electrode has a columnar shape protruding from the end surface of the outer can, has a plurality of gas exhaust ports opened on the outer peripheral surface of the columnar shape, and has an electrode window. The lower end of the formed tapered surface is lower than the upper opening edge of the gas discharge port.

According to the above configuration, the exhaust gas injected from the gas exhaust port can reliably collide with the tapered surface, and the exhaust gas can be diffused along the tapered surface.

In the battery pack according to the fifth embodiment of the present invention, the outer shape of the convex electrode is cylindrical, and the tapered surface is shaped along the side surface of an inverted truncated cone.

According to the above configuration, the exhaust gas discharged from the gas exhaust port provided on the outer circumferential surface of the cylindrical convex electrode is made to flow along the tapered surface of the inverted truncated cone shape and diffused radially, thereby creating an ideal state. The energy contained in high-temperature, high-pressure exhaust gas can be reduced.

In the battery pack according to the sixth embodiment of the present invention, the inclination angle (α) of the tapered surface with respect to the end surface of the outer can is 30 degrees to 60 degrees.

According to the above configuration, the vertical component of the collision velocity when the exhaust gas that has passed through the tapered surface collides with the opposing plate part in an inclined direction is reduced to 0.5 to 0.87 times the collision velocity. Can be done. Therefore, it is possible to effectively reduce the vertical component of the kinetic energy when colliding with the opposing plate portion, thereby suppressing the adverse effects on the opposing plate portion.

In the battery pack according to the seventh embodiment of the present invention, the minimum internal diameter of the tapered surface is larger than the external diameter of the convex electrode.

According to the above configuration, by making the minimum internal diameter of the tapered surface larger than the outer diameter of the convex electrode, the tapered surface is placed away from the gas exhaust port of the convex electrode, and the tapered surface is exposed to high temperature and high pressure. can be protected from exhaust gases. Furthermore, since the lower end opening of the tapered surface can be made larger than the outer shape of the convex electrode, the convex electrode can be quickly guided to the electrode window.

In the battery pack according to the eighth embodiment of the present invention, a recess is formed in the middle part of the tapered surface in the height direction.

According to the above configuration, since the recess is formed in the middle part of the tapered surface, a part of the exhaust gas flowing along the tapered surface is caused to convect in this recess, thereby causing turbulence in the flow of the exhaust gas. This allows the kinetic energy of the exhaust gas to be reduced.

The battery pack according to the ninth embodiment of the present invention includes a recess formed along the upper edge of the tapered surface at the opening edge of the electrode window, and the recess is connected to the upper edge of the tapered surface. It consists of a stepped surface and an upright surface that is connected to the outer periphery of the stepped surface and protrudes to a lower height than the extended surface of the tapered surface.

According to the above configuration, since a recess is formed at the opening edge of the electrode window and at the upper end of the tapered surface, a part of the exhaust gas flowing along the tapered surface is caused to convect into this recess, thereby allowing the exhaust gas to be discharged. Turbulence can be created in the gas flow, thereby reducing the kinetic energy of the exhaust gas. In particular, since the upper end of the upright surface that forms the recess is formed to be lower than the extended surface of the tapered surface, it is possible to prevent the exhaust gas flowing along the tapered surface from colliding with the upright surface and being bent in the vertical direction. Can be effectively prevented.

The battery pack according to the tenth embodiment of the present invention further includes a lead plate connected to the electrode of the battery cell, and a recess provided in the electrode window is used for positioning the lead plate in a fixed position. It is a concave part.

According to the above configuration, by using the recess provided in the electrode window as the positioning part of the lead plate, the lead plate can be easily placed in the fixed position of the electrode window, while a part of the exhaust gas flowing along the tapered surface can be removed. The kinetic energy of the exhaust gas can be reduced by causing it to convect in the recess.

In the battery pack according to the eleventh embodiment of the present invention, the battery holder has at least the tapered surface formed of glass epoxy resin or thermosetting resin.

According to the above configuration, by forming the tapered surface of the battery holder with a heat-resistant resin such as glass epoxy resin or thermosetting resin, it is effective to prevent the tapered surface of high-temperature and high-pressure exhaust gas from being damaged or melted. This allows the exhaust gas to flow stably and diffuse.

In the battery pack according to the twelfth embodiment of the present invention, the battery holder further includes a ring member connected to the end plate portion and forming a tapered surface of the electrode window.

According to the above configuration, the tapered surface of the electrode window is constructed by connecting the ring member formed as a separate member from the battery holder to the end plate part, so while selecting the most suitable material for the battery holder and the ring member, , it is possible to realize a battery holder that can handle exhaust gas under ideal conditions.

In the battery pack according to the thirteenth embodiment of the present invention, a ring member is inserted into the end plate portion and placed at a fixed position.

In the battery pack according to the fourteenth embodiment of the present invention, the ring member is disposed in a fixed position on the end plate portion by locking, press-fitting, adhering, fitting, or screwing.

In the battery pack according to the fifteenth embodiment of the present invention, the ring member is molded from any one of glass epoxy resin, thermosetting resin, and heat-resistant rubber.

In the battery pack according to the sixteenth embodiment of the present invention, the ring member is molded from an inorganic material.

In the battery pack according to the seventeenth embodiment of the present invention, the ring member is molded from either mica or ceramic.

Embodiments of the present invention will be described below based on the drawings. However, the embodiment shown below is an illustration for embodying the technical idea of the present invention, and the present invention is not limited to the following. Moreover, this specification does not in any way specify the members shown in the claims to the members of the embodiments. In particular, the dimensions, materials, shapes, relative arrangements, etc. of the constituent members described in the embodiments are not intended to limit the scope of the present invention, unless specifically stated, and are merely illustrative examples. It's nothing more than that. Note that the sizes, positional relationships, etc. of members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same names and symbols indicate the same or homogeneous members, and detailed descriptions will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured so that a plurality of elements are made of the same member so that one member serves as a plurality of elements, or conversely, the function of one member may be performed by a plurality of members. It can also be accomplished by sharing. Moreover, some of the contents described in some examples and embodiments can be used in other examples and embodiments.

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

A battery pack according to an embodiment of the present invention is shown in FIGS. 1 to 4. The battery pack 100 shown in these figures includes a battery cell 1 with electrodes at both ends of a cylindrical outer can 11, and a discharge valve (not shown) that opens when the internal pressure exceeds a set pressure. The battery holder 2 is provided with a battery holder 2 for positioning and holding, and a facing plate portion 4 provided on the end surface side of the battery cell 1 held in the battery holder 2 so as to be spaced apart from the end surface of the battery cell 1. A battery pack 100 shown in FIGS. 1 to 3 has a plurality of battery cells 1 arranged in a fixed position in a battery holder 2, and the battery holder 2 holding the plurality of battery cells 1 is housed in an exterior case 3. ing. A battery pack 100 shown in FIG. 1 has a battery core pack 10 in which end electrodes at both ends of a plurality of battery cells 1 arranged in a fixed position in a battery holder 2 are connected with a lead plate 5. A pack 10 is stored in an outer case 3. In this battery pack 100, the facing plate portion 4 provided so as to be spaced apart from the end surface of the battery cell 1 serves as an exterior case 3.

(Battery cell 1)
The battery cell 1 has positive and negative electrodes at both ends of a cylindrical outer can 11, with one electrode serving as a convex electrode 13 and the other electrode serving as a flat electrode 14. The battery cell 1 shown in the figure is a cylindrical battery. In the cylindrical battery, an electrode body is housed in a cylindrical outer can 11, an electrolyte is filled, and the opening of the outer can 11 is sealed with a sealing plate (not shown). In the cylindrical battery, a convex electrode 13 is provided on one end surface 11A of an outer can 11 closed with a sealing plate, and positive and negative electrodes are provided as a flat electrode 14 on the bottom surface 11B of the outer can, which is the other end surface. . A plurality of battery cells 1 having positive and negative electrodes at both ends are arranged parallel to the battery holder 2, and the electrodes at both ends are exposed through the electrode windows 23 and 24 of the battery holder 2, and are connected to the lead plate 5. connected in parallel and/or series.

Furthermore, the battery cell 1 is equipped with a discharge valve (not shown) that opens when the internal pressure exceeds a set pressure inside the convex electrode 13, and a gas exhaust port 16 is provided on the outer peripheral surface of the convex electrode 13. It's open. The convex electrode 13 in FIG. 3 has a columnar outer shape, and has a plurality of gas exhaust ports 16 opened along the outer peripheral surface. Note that in this specification, the gas exhaust port opened in the convex electrode is preferably opened in the side surface of the columnar convex electrode 13, as shown in FIG. However, the gas discharge port may be opened from the side surface of the convex electrode to the end surface of the outer can, or may be opened from the side surface of the convex electrode to the tip surface of the convex electrode. .

Battery cell 1 is a lithium ion battery. The battery cell 1, which is a lithium ion battery, can have an outer case made of aluminum or an aluminum alloy. However, the present invention does not specify the battery cell to be a lithium ion battery, and all secondary batteries currently used and to be developed in the future can be used, such as other non-aqueous electrolyte secondary batteries and nickel-metal hydride batteries.

(Battery holder 2)
As shown in FIGS. 1 to 3, the battery holder 2 has a plurality of battery cells 1 arranged in parallel positions with both end surfaces of the battery cells 1 on the same plane. In this battery holder 2, convex electrodes 13 and flat electrodes 14 provided on both end faces of the battery cell 1 are arranged on the same plane and exposed through electrode windows 23 and 24. The battery holder 2 has a peripheral wall portion 21 that covers the outer peripheral surface of the end portion of the battery cell 1 and an end plate portion 22 that faces the end surface 11A of the outer can 11 of the battery cell 1. The illustrated battery holder 2 is provided with a plurality of battery storage sections 20 in which each battery cell 1 is stored using the peripheral wall section 21 and the end plate section 22.

The battery cell 1 is inserted into the battery storage part 20 and placed in a fixed position. In the battery storage section 20, the inner circumferential surface of the peripheral wall section 21 has an inner shape that follows the outer circumferential surface of the battery cell 1, and the battery cell 1 is inserted therein and arranged at a fixed position. In the illustrated battery holder 2, the battery storage portion 20 is cylindrical and a cylindrical battery is placed in a fixed position. The cylindrical battery storage section 20 has an inner diameter slightly larger than an outer diameter of the cylindrical battery in order to insert the cylindrical battery and arrange it in a fixed position. In this battery holder 2, the surface of a peripheral wall portion 21 disposed between adjacent cylindrical batteries has a shape that follows the surface of the cylindrical batteries. Further, in the battery holder 2, both ends of the battery storage section 20 in which the battery cell 1 is inserted and held are closed with end plate sections 22, and both ends of the outer can 11 of the battery cell 1 stored in the battery storage section 20 are closed. Positioning the surface.

The battery holder 2 shown in FIG. 3 has a shape in which a plurality of battery storage sections 20 are arranged in multiple rows and stages in parallel positions in a stacked state. The battery holder 2 having this structure has the feature that the cylindrical batteries can be arranged in a space efficient manner and the whole can be made compact. Additionally, by saving resin in the valleys, the amount of resin used can be reduced, reducing manufacturing costs and weight. However, in the battery holder 2, cylindrical batteries arranged in multiple stages and rows can be arranged vertically and horizontally, and the cylindrical batteries can be arranged at the intersections of a checkerboard grid. Furthermore, the battery holder does not necessarily have to have a cylindrical battery housing, but can also have a polygonal column shape capable of accommodating a cylindrical battery, such as a regular hexagonal column or a regular octagonal column.

Furthermore, the battery holder 2 shown in FIGS. 1 to 4 is divided into a pair of holder units 2A and 2B at the axial center of the battery cell 1. The battery holder 2 shown in the figure has a peripheral wall portion 21 divided into two parts in the middle in the axial direction, and a battery storage portion 20 is provided in each of the pair of holder units 2A and 2B. In this battery holder 2, both ends of the battery cell 1 are inserted into the battery storage parts 20 of a pair of holder units 2A and 2B, and the battery cell 1 is sandwiched and held from both sides by the pair of holder units 2A and 2B. .

As shown in FIG. 1, the pair of holder units 2A and 2B are connected to each other by screwing a set screw 27 passing through one holder unit 2B into the other holder unit 2A. In FIG. 1, the holder unit 2A located on the upper side is equipped with a connecting boss 25 into which the set screw 27 is screwed, and the holder unit 2B located on the lower side is integrally molded with a connecting protrusion 26 through which the set screw 27 is inserted. It is set up. The pair of holder units 2A and 2B are connected by a set screw 27 passing through the connecting convex portion 26 and screwed into the connecting boss 25. In this state, the battery cells 1 stored in the opposing battery storage parts 20 are held in a state where they are sandwiched between the holder units 2A and 2B from both ends and press-fitted into the battery storage parts 20.

(electrode window 23)
The end plate portion 22 has electrode windows 23 and 24 that expose the electrodes at both ends of the battery cell 1, and the lead plate 5 can be connected to the electrodes of the battery cell 1 exposed through the electrode windows 23 and 24. ing. The electrode windows 23 and 24 are smaller than the outer shape of the battery cell 1, and allow the electrodes at both ends of the battery cell 1 to be exposed when the battery cell 1 is placed in a fixed position in the battery storage section 20.

Furthermore, the end plate portion 22 disposed on the convex electrode 13 side of the battery cell 1 has a tapered surface 6 on the inner peripheral surface of the electrode window 23 that exposes the convex electrode 13. This tapered surface 6 is formed so that its internal shape gradually increases in the direction away from the end surface of the outer can 11. The tapered surface 6 shown in the figure is an inclined surface along the side surface of an inverted truncated cone. The tapered surface 6 of the electrode window 23 is provided at a position facing the gas exhaust port 16 provided on the convex electrode 13, and as shown by the arrow in FIG. He is trying to make it flow from below to above along the tapered surface 6.

As shown in FIG. 4, the tapered surface 6 formed on the inner peripheral surface of the electrode window 23 is formed so that its upper end is higher than the upper opening edge 16a of the gas exhaust port 16, and its lower end is It is formed to be lower than the upper opening edge 16a of the outlet 16. This tapered surface 6 allows the exhaust gas injected from the gas outlet 16 to collide with the tapered surface 6 reliably, and allows the exhaust gas to flow along the tapered surface 6. The lower end of the tapered surface 6 is preferably designed to be lower than the midline between the upper opening edge 16a and the lower opening edge 16b of the gas discharge port 16. The tapered surface 6 shown in the figure is formed such that its lower end is lower than the lower end opening edge 16b of the gas discharge port 16. This tapered surface 6 ensures that the exhaust gas injected from the vicinity of the lower end opening edge 16b of the gas discharge port 16 also collides with the tapered surface 6, so that the entire exhaust gas can flow along the tapered surface 6. Note that in this specification, the vertical direction is specified in the drawings. That is, in the convex electrode 13 shown in FIG. 4, the tip surface 13a is the upper end, and the end surface 11A side of the outer can 11 is the lower end.

Further, the tapered surface 6 has a minimum internal shape larger than the external shape of the convex electrode 13. The tapered surface 6 shown in FIG. 4 is formed so that the inner diameter (d1) at the lower edge is the minimum inner diameter and is larger than the outer diameter (D1) of the convex electrode 13. The inner diameter (d1) that is the minimum inner diameter of the tapered surface 6 is, for example, 1 to 2 times, preferably 1.2 to 1.8 times, more preferably 1. It can be increased by 4 to 1.6 times. Further, the inner diameter (d1), which is the minimum inner diameter of the tapered surface 6, is smaller than the outer diameter (D2) of the battery cell 1, for example, 0.5 to 0.9 times the outer diameter (D2) of the battery cell 1. , preferably 0.6 to 0.8 times. The battery holder 2 in which the inner diameter (d1) of the lower edge, which is the minimum inner diameter of the tapered surface 6, is in the above range is arranged with the tapered surface 6 spaced apart from the gas discharge port 16 of the convex electrode 13, While protecting the tapered surface 6 from high-temperature and high-pressure exhaust gas, the exhaust gas can be diffused while ideally flowing.

Furthermore, the tapered surface 6 has a maximum inner diameter smaller than the outer diameter of the battery cell 1. The tapered surface 6 shown in FIG. 4 is formed so that the inner diameter (d2) at the upper edge is the largest inner diameter and smaller than the outer diameter (D2) of the battery cell 1. According to this structure, the area in which the end face plate portion 22 holds the end face of the battery cell 1 is widened, and the battery cell 1 can be firmly held.

The tapered surface 6 described above can have an inclination angle α of 30 degrees to 60 degrees with respect to the end surface 11A of the outer can 11. The tapered surface 6 having the inclination angle α in the above range can reduce the impact when the exhaust gas passing through the tapered surface 6 collides with the opposing plate portion 4 disposed on the convex electrode 13 side of the battery cell 1. The battery pack 100 shown in FIG. 1 includes a facing plate portion 4 provided on the convex electrode 13 side of the battery cell 1 held in the battery holder 2 so as to be spaced apart from the end surface of the battery cell 1. This opposing plate portion 4 is a member that regulates the flow of exhaust gas, and the opposing plate portion 4 shown in the figure is a wall surface of the exterior case 3. However, the opposing plate portion may be a separate member from the exterior case 3 and may be a plate material disposed between the inner surface of the exterior case 3 and the battery holder 2.

In this way, the opposing plate part 4 disposed on the convex electrode 13 side of the battery cell 1 is affected by the collision of the high temperature and high pressure exhaust gas injected from the gas exhaust port 16, but as shown in FIG. As shown, by forming the inner circumferential surface of the electrode window 23 into a tapered surface 6, the exhaust gas is made to flow while being inclined, and the vertical component of the collision velocity when it collides with the opposing plate portion 4 in an inclined direction. can be reduced. For example, the tapered surface 6 with an inclination angle α of 60 degrees can reduce the vertical component of the collision velocity of the exhaust gas colliding with the opposing plate portion 4 to 0.87 times the collision velocity, and the inclination angle α can be reduced to 30 degrees. The tapered surface 6 can reduce the vertical component of the collision velocity to 0.5 times the collision velocity. Furthermore, by making the exhaust gas flow along the tapered surface 6, the diffusion area of the exhaust gas that is radially diffused around the convex electrode 13 is widened, and the thermal energy and kinetic energy of the exhaust gas are more effectively reduced. Energy can be reduced. Therefore, the energy when colliding with the exterior case 3, which is the opposing plate part 4, is effectively reduced, and the adverse effects caused by high-temperature and high-pressure exhaust gas, such as damage or melting of the exterior case, are suppressed. This can prevent high-temperature, high-pressure exhaust gas from being directly injected to the outside of the exterior case from near the end face of the battery cell.

(Other examples of electrode windows)
Furthermore, the inner peripheral surface of the electrode window 23 can also have the structure shown in FIG. The electrode window 23 shown in this figure has a tapered surface 6 from the lower end to the upper end of the inner circumferential surface, and a recess 7 in the middle of the tapered surface 6 in the height direction. The recessed portion 7 shown in the figure is a stepped recessed portion having a right triangular cross-sectional view, and the upper portion of the stepped recessed portion is open and is formed at a position higher than the tip surface 13a of the convex electrode 13. There is. This tapered surface 6 includes a first tapered surface 6A formed below the recess 7 and a second tapered surface 6B formed above the recess 7. It is provided on the extended surface of the first tapered surface 6A. The tapered surface 6 of this structure has a concave portion 7 provided in the intermediate portion, which causes a part of the exhaust gas flowing along the tapered surface 6 to convect into the concave portion 7, causing turbulence in the flow of the exhaust gas and discharging it. The kinetic energy of gas can be reduced.

Further, in the electrode window 23 shown in FIG. 5, a recess 7 provided in the middle of the tapered surface 6 is used as a positioning recess for arranging the lead plate 5 connected to the electrode of the battery cell 1 in a fixed position. This structure uses the recess 7 provided in the electrode window 23 as a positioning part for the lead plate 5, and allows a part of the exhaust gas flowing along the tapered surface 6 to convect into the recess 7, so that the kinetic energy of the exhaust gas is can be reduced.

Furthermore, the inner circumferential surface of the electrode window 23 can also have the structure shown in FIG. The electrode window 23 shown in this figure includes a recess 7 formed along the upper edge of the tapered surface 6 at the opening edge. This recess 7 is also a step recess having a right triangular shape in cross-sectional view, and includes a step surface 7a connected to the upper edge of the tapered surface 6, and an upright surface 7b connected to the outer peripheral edge of this step surface 7a. It consists of This raised surface 7b protrudes to a height lower than the extended surface of the tapered surface 6. In other words, the upper end position of the raised surface 7b is lower than the extended surface of the tapered surface 6. The electrode window 23 described above is an opening edge, and by forming a recess 7 at the upper end of the tapered surface 6, a part of the exhaust gas flowing along the tapered surface is caused to convect into the recess 7 and is discharged. The kinetic energy of exhaust gas can be reduced by creating turbulence in the gas flow. Furthermore, by making the upright surface 7b forming the recess 7 lower than the extended surface of the tapered surface 6, it is effective to prevent the exhaust gas flowing along the tapered surface 6 from colliding with the upright surface 7b and being bent in the vertical direction. can be prevented.

Furthermore, the electrode window 23 shown in FIG. 6 also has a recess 7 provided above the tapered surface 6 as a positioning recess for arranging the lead plate 5 connected to the electrode of the battery cell 1 in a fixed position. This structure also uses the concave part 7 provided in the electrode window 23 as a positioning part for the lead plate 5, and makes a part of the exhaust gas flowing along the tapered surface 6 convect to the concave part 7, thereby generating kinetic energy of the exhaust gas. can be reduced.

The battery holder 2 described above is molded into a predetermined shape using resin, which is an insulating material. The battery holder 2 can preferably be made of resin with excellent flame retardancy. Such a resin may be, for example, a thermosetting resin such as a glass epoxy resin or an unsaturated polyester. However, in the battery holder, at least the portion constituting the tapered surface 6 of the electrode window 23 can be made of resin with excellent flame retardancy such as glass epoxy resin or thermosetting resin. In this case, other parts of the battery holder, such as the peripheral wall part and a part of the end plate part, can also be molded from thermoplastic resin such as PC (polycarbonate) or PP (polypropylene).

Furthermore, in the battery holder 2, the tapered surface 6 of the electrode window 23 can be made of a separate member. The battery holder 2 shown in FIG. 7 includes a ring member 8 connected to the end plate portion 22 and forming the tapered surface 6 of the electrode window 23. The ring member 8 has an electrode window 23 for guiding the convex electrode 13, and the shape of the tapered surface 6 is similar to the above-described tapered surface 6 shown in FIG. Such a ring member 8 is a separate member from the battery holder 2, and can be manufactured from a material with excellent heat resistance. The ring member 8 can be made of, for example, a thermosetting resin such as glass epoxy resin or unsaturated polyester, or made of heat-resistant rubber, or made of an inorganic material. Examples of inorganic materials with excellent heat resistance that can be used include mica, heat-insulating ceramics, and alumina ceramics. In this way, the structure in which the ring member 8 formed as a separate member from the battery holder 2 is connected to the end plate part 22 is such that the peripheral wall part 21 and the end plate part 22 of the battery holder 2 are molded with inexpensive thermoplastic resin or the like. However, by manufacturing the ring member 8 having the tapered surface 6 from a material with excellent heat resistance, it becomes possible to deal with exhaust gas in an ideal state.

As described above, the ring member 8 manufactured separately from the battery holder 2 can preferably be inserted into the end plate portion 22 and placed in a fixed position. The ring member 8 shown in FIG. 7 has a tapered surface 6 formed on its inner circumferential surface, and an anchor portion 8a that projects in the radial direction is integrally formed on its outer circumferential surface. This ring member 8 is firmly connected to the end plate portion 22 by inserting the anchor portion 8a into the end plate portion 22 molded from resin.

Further, although not shown, the ring member may have a connecting hole formed in the end plate portion that follows the outer shape of the ring member, and the ring member may be inserted into this connecting hole to connect to the battery holder at a fixed position. . This ring member can be connected to the connection hole of the end plate portion by a method such as locking, press-fitting, adhesion, fitting, or screwing.

(Exterior case 3)
The exterior case 3 houses a battery holder 2 that holds a plurality of battery cells 1 in a fixed position. The exterior case 3 shown in the figure has a structure in which a box-shaped first case and a second case that are divided into two halves are connected at an opening edge, and a battery holder 2 is housed inside. The exterior case 3 is molded from resin, which is an insulating material. This exterior case 3 has a wall surface facing the convex electrode 13 of the battery cell 1 housed therein as a facing plate portion 4 .

(Lead plate 5)
The lead plate 5 connects a plurality of cylindrical batteries arranged in multiple stages and rows in a predetermined arrangement. The lead plate 5 connects a plurality of cylindrical batteries in parallel, in series, or in series and parallel. The lead plate 5 is a metal plate and is electrically connected to the end electrode of the cylindrical battery by ultrasonic welding, resistance welding, or laser welding. In particular, when the lead plate 5 is made of aluminum or an aluminum alloy and the outer can of the cylindrical battery is made of aluminum or an aluminum alloy, connection by resistance welding becomes difficult because aluminum has low electrical resistance. Therefore, in such a case, it is preferable to weld the lead plate 5 to the end electrode by ultrasonic welding.

Furthermore, the reed plate 5 can have a fuse link that is melted by the heat of the exhaust gas injected from the gas exhaust port 16 when the exhaust valve is opened. This lead plate 5 can constitute a fuse link by connecting the connecting portion connected to the convex electrode 13 and the main body portion of the lead plate 5 with an elongated connecting portion. In this structure, by providing a fuse link that blows the lead plate 5 when exhaust gas is discharged, unintended conduction can be avoided and safety can be improved.

The battery pack of the present invention is a battery pack having a structure in which a battery cell equipped with a discharge valve is held in a fixed position by a battery holder and stored in an exterior case, and the high temperature and high pressure discharged from the discharge valve of the battery cell is discharged. It can be suitably used for electric equipment, etc. as a battery pack that can suppress damage to the exterior case etc. due to gas.

100...Battery pack 1...Battery cell 2...Battery holder 2A...Holder unit 2B...Holder unit 3...Exterior case 4...Opposing plate portion 5...Lead plate 6...Tapered surface 6A...First tapered surface 6B...Second taper Surface 7...Concave portion 7a...Step surface 7b...Elevated surface 8...Ring member 8a...Anchor portion 10...Core pack 11...Exterior can 11A...End surface 11B...Bottom surface 13...Convex electrode 13a...Tip surface 14...Flat electrode 16...Gas Discharge port 16a...Upper end opening edge 16b...Lower end opening edge 20...Battery storage section 21...Peripheral wall section 22...End plate section 23...Electrode window 24...Electrode window 25...Connection boss 26...Connection protrusion 27...Set screw 101...Battery Cell 102...Battery holder 103...Exterior case 104...Opposing plate part 106...Vertical surface 113...Convex electrode 116...Gas outlet 122...End face plate part 123...Electrode window

Claims (16)

one or more battery cells having electrodes at both ends of a cylindrical outer can and equipped with a discharge valve that opens when the internal pressure exceeds a set pressure;
a battery holder that positions and holds the battery cell;
A battery pack comprising an opposing plate portion provided on an end surface side of the battery cell held in the battery holder so as to be spaced apart from the end surface of the battery cell,
The battery cell has one electrode as a convex electrode, the discharge valve is provided inside the convex electrode, and a gas exhaust port is opened on the outer peripheral surface of the convex electrode,
The battery holder includes:
a peripheral wall portion that covers the outer peripheral surface of the end portion of the battery cell;
comprising an end plate portion facing the end surface of the outer can of the battery cell,
The end plate portion disposed on the convex electrode side of the battery cell has an electrode window that exposes the convex electrode, and has an electrode window on the inner peripheral surface of the electrode window in a direction away from the end surface of the outer can. It has a tapered surface that is inclined so that the inner shape gradually increases toward the
The convex electrode has a columnar shape protruding from an end surface of the outer can, and has a plurality of gas discharge ports opened on the outer peripheral surface of the columnar shape,
A battery pack characterized in that a lower end of the tapered surface formed in the electrode window is lower than an upper opening edge of the gas discharge port . The battery pack according to claim 1, further comprising:
an exterior case that houses the battery holder holding the battery cell;
A battery pack characterized in that the opposing plate portion is a wall surface of the outer case. The battery pack according to claim 1 or 2,
The convex electrode has a columnar shape protruding from an end surface of the outer can, and has a plurality of gas discharge ports opened on the outer peripheral surface of the columnar shape,
A battery pack characterized in that an upper end of a tapered surface formed in the electrode window is higher than an upper opening edge of the gas discharge port. A battery pack according to any one of claims 1 to 3 ,
The outer shape of the convex electrode is cylindrical,
A battery pack, wherein the tapered surface has a shape that follows a side surface of an inverted truncated cone. A battery pack according to any one of claims 1 to 4 ,
A battery pack characterized in that an inclination angle (α) of the tapered surface with respect to an end surface of the outer can is 30 degrees to 60 degrees. A battery pack according to any one of claims 1 to 5 ,
A battery pack characterized in that a minimum internal diameter of the tapered surface is larger than an external diameter of the convex electrode. one or more battery cells having electrodes at both ends of a cylindrical outer can and equipped with a discharge valve that opens when the internal pressure exceeds a set pressure;
a battery holder that positions and holds the battery cell;
an opposing plate portion provided on the end surface side of the battery cell held in the battery holder so as to be spaced apart from the end surface of the battery cell;
A battery pack comprising:
The battery cell has one electrode as a convex electrode, the discharge valve is provided inside the convex electrode, and a gas exhaust port is opened on the outer peripheral surface of the convex electrode,
The battery holder includes:
a peripheral wall portion that covers the outer peripheral surface of the end portion of the battery cell;
comprising an end plate portion facing the end surface of the outer can of the battery cell,
The end plate portion disposed on the convex electrode side of the battery cell has an electrode window that exposes the convex electrode, and has an electrode window on the inner peripheral surface of the electrode window in a direction away from the end surface of the outer can. It has a tapered surface that is inclined so that the inner shape gradually increases toward the
A battery pack characterized in that a recess is formed in the middle part of the tapered surface in the height direction. one or more battery cells having electrodes at both ends of a cylindrical outer can and equipped with a discharge valve that opens when the internal pressure exceeds a set pressure;
a battery holder that positions and holds the battery cell;
an opposing plate portion provided on the end surface side of the battery cell held in the battery holder so as to be spaced apart from the end surface of the battery cell;
A battery pack comprising:
The battery cell has one electrode as a convex electrode, the discharge valve is provided inside the convex electrode, and a gas exhaust port is opened on the outer peripheral surface of the convex electrode,
The battery holder includes:
a peripheral wall portion that covers the outer peripheral surface of the end portion of the battery cell;
comprising an end plate portion facing the end surface of the outer can of the battery cell,
The end plate portion disposed on the convex electrode side of the battery cell has an electrode window that exposes the convex electrode, and has an electrode window on the inner peripheral surface of the electrode window in a direction away from the end surface of the outer can. It has a tapered surface that is inclined so that the inner shape gradually increases toward the
The opening edge of the electrode window includes a recess formed along the upper edge of the tapered surface,
The recess includes a stepped surface connected to the upper edge of the tapered surface, and an upright surface connected to the outer peripheral edge of the stepped surface and projected to a lower height than the extended surface of the tapered surface. A battery pack characterized by: The battery pack according to claim 7 or 8 , further comprising:
comprising a lead plate connected to the electrode of the battery cell,
A battery pack characterized in that the recess provided in the electrode window serves as a positioning recess for arranging the lead plate in a fixed position. Claims 1 to 9 also provide a battery pack according to any one of claims 1 to 9 ,
A battery pack, wherein the battery holder has at least the tapered surface formed of glass epoxy resin or thermosetting resin. one or more battery cells having electrodes at both ends of a cylindrical outer can and equipped with a discharge valve that opens when the internal pressure exceeds a set pressure;
a battery holder that positions and holds the battery cell;
an opposing plate portion provided on the end surface side of the battery cell held in the battery holder so as to be spaced apart from the end surface of the battery cell;
A battery pack comprising:
The battery cell has one electrode as a convex electrode, the discharge valve is provided inside the convex electrode, and a gas exhaust port is opened on the outer peripheral surface of the convex electrode,
The battery holder includes:
a peripheral wall portion that covers the outer peripheral surface of the end portion of the battery cell;
comprising an end plate portion facing the end surface of the outer can of the battery cell,
The end plate portion disposed on the convex electrode side of the battery cell has an electrode window that exposes the convex electrode, and has an electrode window on the inner peripheral surface of the electrode window in a direction away from the end surface of the outer can. It has a tapered surface that is inclined so that the inner shape gradually increases toward the
A battery pack characterized in that the battery holder includes a ring member connected to the end plate portion and forming the tapered surface of the electrode window. The battery pack according to claim 11 ,
A battery pack characterized in that the ring member is inserted into the end plate portion and placed at a fixed position. The battery pack according to claim 11 ,
A battery pack characterized in that the ring member is connected to the end plate portion by any one of locking, press-fitting, adhesion, fitting, and screwing and is arranged in a fixed position. A battery pack according to any one of claims 11 to 13 ,
A battery pack characterized in that the ring member is molded from any one of glass epoxy resin, thermosetting resin, and heat-resistant rubber. A battery pack according to any one of claims 11 to 13 ,
A battery pack characterized in that the ring member is molded from an inorganic material. The battery pack according to claim 15 ,
A battery pack characterized in that the ring member is molded from either mica or ceramic.

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