Battery module

Abstract

The present invention realizes a high level of safety by preventing harmful effects resulting from solid discharge from a can-bottom valve that opens.　A battery module according to the present invention comprises: a plurality of cylindrical batteries (1); and a lead plate (3) that is connected to the cylindrical batteries (1) and electrically connects the plurality of cylindrical batteries (1). Each of the cylindrical batteries (1) has a can-bottom valve (16) comprising a thin-walled line that breaks, when the internal pressure of an exterior can exceeds a threshold pressure, and opens a discharge port. The lead plate (3) comprises: a double-holding arm (31) that is arranged so as to oppose the can bottom of the cylindrical batteries (1) and is obtained by connecting both ends to the lead plate (3) at positions opposing the can-bottom valve (16); and a gas permeation gap (32) for discharged gas ejected from the discharge port, the gas permeation gap (32) being located on both sides of the double-holding arm (31).

Description

[Technical Field]

[0001] The present invention relates to a battery module in which cylindrical batteries are connected by metal lead plates, and more particularly to a battery module in which cylindrical batteries equipped with can bottom valves are connected by lead plates. [Background technology]

[0002] Battery modules have been developed in which multiple cylindrical batteries are connected in series or parallel by welding lead plates to the electrode terminals at the ends (see Patent Documents 1 and 2). The battery modules described in these publications consist of multiple cylindrical batteries arranged in a parallel position with the electrode surfaces on both ends on the same plane. Lead plates on both ends of the cylindrical batteries have connecting arms, the tips of which are welded to the electrode terminals. The above battery modules are equipped with a bottom valve on the cylindrical batteries to prevent the batteries from bursting due to an abnormally high internal pressure caused by, for example, an internal short circuit. The bottom valve opens when the internal pressure exceeds a threshold pressure to prevent an abnormal increase in internal pressure. In particular, non-aqueous electrolyte secondary batteries such as lithium-ion batteries experience a sudden increase in internal pressure when they experience thermal runaway due to an internal short circuit, so the bottom valve allows for the rapid release of waste.

[0003] The can bottom valve has a ring-shaped thin wall line at the bottom of the can, which breaks when internal pressure increases, opening the valve. This structure allows for a large opening area, preventing a sudden increase in internal pressure. However, when this can bottom valve opens, solid waste, such as electrode materials, is ejected along with high-temperature gas from the large opening at the outlet, causing various problems. For example, if conductive solid waste is ejected from a cylindrical battery into the battery module case, it can come into contact with exposed conductive parts inside the case and cause a short circuit. Furthermore, the can bottom valve opens under abnormal conditions such as thermal runaway, and the solid waste ejected from the bottom of the can reaches an abnormally high temperature of over 500°C, which can cause thermal damage if it is ejected into the case. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5737481 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-84603 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention was developed with the aim of preventing the above-mentioned problems, and an important object of the present invention is to provide a battery module that can achieve higher safety by preventing the problems caused by solid matter discharged from the opening bottom valve of the can. [Means for solving the problem]

[0006] A battery module according to one embodiment of the present invention includes a plurality of cylindrical batteries and lead plates connected to the cylindrical batteries to electrically connect the plurality of cylindrical batteries. The cylindrical batteries have a can bottom valve formed by a thin-walled line that ruptures to open a discharge port when the internal pressure of the outer can exceeds a threshold pressure. The lead plate is disposed opposite the bottom of the cylindrical batteries and has, at a position opposite the can bottom valve, a double-supported arm connected at both ends to the lead plate, and gas permeation gaps on both sides of the double-supported arm for exhaust gas ejected from the discharge port. [Effects of the Invention]

[0007] The above battery module prevents harmful effects caused by high-temperature solid matter discharged from the opening bottom valve, thereby realizing higher safety. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view of a battery module according to an embodiment of the present invention; [Figure 2] FIG. 2 is an enlarged perspective view of a battery unit of the battery module shown in FIG. [Figure 3]FIG. 3 is a schematic cross-sectional perspective view of the battery unit shown in FIG. 2. [Figure 4] FIG. 3 is an enlarged plan view of the battery unit shown in FIG. [Figure 5] 5 is a vertical cross-sectional view taken along the line VV of the battery unit shown in FIG. 4. [Figure 6] FIG. 1 is a perspective view showing an example of a cylindrical battery. [Figure 7] FIG. 10 is a perspective view showing another example of a cylindrical battery. [Figure 8] 8 is an enlarged plan view of a battery unit including the cylindrical battery shown in FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0009] A battery module according to one embodiment of the present invention comprises a plurality of cylindrical batteries and lead plates connected to the cylindrical batteries to electrically connect the plurality of cylindrical batteries, wherein the cylindrical batteries have a can bottom valve consisting of a thin-walled line that breaks to open an exhaust port when the internal pressure of the outer can exceeds a threshold pressure, and the lead plate is arranged opposite the can bottom of the cylindrical batteries, and has, at a position opposite the can bottom valve, a double-supported arm whose both ends are connected to the lead plate, and gas permeation gaps on both sides of the double-supported arm for exhaust gas ejected from the exhaust port.

[0010] The above configuration allows high-temperature exhaust gases discharged from the bottom valve at the can bottom to pass through the gas permeation gaps in the lead plates, while the lead plates prevent the permeation of high-temperature solid effluent. This achieves high safety, an extremely important characteristic of battery modules. This battery module achieves this by providing a double-supported arm connected at both ends to the lead plate, located opposite the bottom valve, on the lead plate facing the can bottom of the cylindrical battery. The arms are connected to the lead plates at both ends, preventing them from breaking when subjected to the impact of the high-temperature effluent forcefully ejected from the bottom valve. This prevents solid effluent from permeating the lead plate. The gas permeation gaps on both sides of the arms allow the high-temperature effluent gas contained in the effluent to pass through, preventing a sudden increase in the battery's internal pressure. When the bottom valve opens, it ejects a mixture of both exhaust gases and solid effluent. The high-temperature effluent gas passes through the gas permeation gaps on both sides of the arms, preventing the solid effluent from permeating. Because cylindrical batteries experience instantaneous increases in internal pressure due to thermal runaway and other factors, it is important to quickly vent exhaust gases from the open bottom valve. A structure that does not allow for smooth exhaust of exhaust gases would result in a sudden increase in the cylindrical battery's internal pressure, making safety unattainable. The battery module described above features a balanced and rapid exhaust of exhaust gases from the bottom valve into the gas permeation gaps on both sides of the double-supported arms, effectively suppressing the buildup of internal pressure in the cylindrical battery. Furthermore, the double-supported arms prevent high-temperature solid waste from passing through the lead plates, preventing obstructions caused by solid waste. However, because both ends of the double-supported arms are connected to the lead plates, they are not deformed by the forceful ejection of waste, effectively preventing the passage of solid waste.

[0011] In a battery module according to another embodiment of the present invention, the arms are arranged so as to extend in the diameter direction of the circular can bottom.

[0012] In the above battery module, the support arms are arranged in the diameter direction of the can bottom and at the center of the circular can bottom, which more effectively prevents the passage of solid waste discharged from the open can bottom valve, thereby achieving greater safety.

[0013] In another embodiment of the battery module of the present invention, the lead plate has a connecting arm welded to the bottom of the can on both sides of the double-supported arm, and a gas permeable gap is provided between the double-supported arm and the connecting arm. Furthermore, the connecting arm is a cantilevered arm with one end connected to the lead plate. connection The arm welds the tip to the bottom of the can.

[0014] The above battery module has a cantilevered connecting arm, one end of which is connected to a lead plate, welded to the bottom of the can, where the double-sided arms are positioned opposite each other, and a gas-permeable gap is provided between the connecting arm and the double-sided arm.This means that the connecting arm welded to the can bottom allows the double-sided arms to be positioned at the bottom on both sides without misalignment, and the double-sided arms can reliably prevent solid waste from passing through.

[0015] In another embodiment of the battery module of the present invention, the cantilevered connecting arm is welded to the bottom of the can outside the annular thin-wall line.

[0016] The above battery module has the advantage that the cantilevered connection arms more reliably prevent misalignment of the double-supported arms, and the cantilevered connection arms are welded to the can bottom to electrically connect the lead plates to the cylindrical batteries, while the can bottom valve can be opened stably with a large opening area. This is because the can bottom valve breaks the thin-wall line, opening the inside of the broken annular part where the cantilevered connection arms are not welded, allowing exhaust gases to be vented.

[0017] In a battery module according to another embodiment of the present invention, the cylindrical battery is provided with a can bottom valve at the bottom of the outer can and a discharge valve on a sealing plate that closes the opening of the outer can.

[0018] The above battery module has the advantage that exhaust gas can be quickly discharged from the bottom valve and exhaust valve provided at both ends of the cylindrical battery, thereby more effectively suppressing an increase in the internal pressure of the battery.

[0019] In a battery module according to another embodiment of the present invention, the width of the arms supported at both ends is set to 1.5 mm or more.

[0020] The battery module described above has the advantage that the arms supported at both ends are strong enough to more reliably prevent the lead plates from penetrating solid waste discharged from the can bottom valve.

[0021] In a battery module according to another embodiment of the present invention, the opening width (K) of the gas permeation gap in a plan view is set to 5 mm or less.

[0022] The above battery module has an opening width (K) of the gas permeation gap of 5 mm or less, which has the advantage of more reliably preventing solid waste discharged from the can bottom valve from passing through the gas permeation gap.

[0023] In a battery module according to another embodiment of the present invention, the cylindrical batteries are non-aqueous electrolyte secondary batteries.

[0024] The above battery modules use non-aqueous electrolyte secondary batteries such as lithium-ion batteries, which can experience thermal runaway and emit high-temperature, high-pressure waste, and have the advantage of being able to increase charge / discharge capacity relative to weight and volume while ensuring high safety.

[0025] The present invention will be described in detail below 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) will be used as necessary. However, the use of these terms is intended to facilitate 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. Furthermore, parts that appear with the same reference numerals in multiple drawings indicate the same or equivalent parts or components. Furthermore, the embodiments shown below are specific examples of the technical concept of the present invention and are not intended to limit the present invention thereto. Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described below are intended as examples and are not intended to limit the scope of the present invention thereto. Furthermore, the content described in one embodiment or example can also be applied to other embodiments or examples. Furthermore, the sizes and positional relationships of components shown in the drawings may be exaggerated for clarity of explanation.

[0026] In conventional battery modules containing multiple cylindrical batteries, lead plates are welded to electrode terminals to connect the cylindrical batteries in series or parallel. Because cylindrical batteries have electrode terminals at both ends, lead plates are positioned facing the electrode surfaces at both ends, with connection arms on the lead plates welded to each electrode surface. The lead plates are cut from thin, deformable metal plates, with cantilevered connection arms connecting one end to the lead plate, and the tip of the connection arm is welded to the cylindrical battery. Cylindrical batteries connected to these lead plates have bottom valves on both ends, the protruding electrode side and the bottom of the can, to more effectively suppress internal pressure buildup. The bottom valve on the protruding electrode side has a slit-shaped exhaust port around the protruding electrode, which limits its opening area. In contrast, the bottom valve on the can bottom is larger than the protruding electrode side, allowing for smoother exhaust of exhaust gases and more effective suppression of internal pressure buildup.

[0027] The bottom valve at the bottom of the battery can is wide open, allowing waste to be smoothly discharged from a cylindrical battery experiencing thermal runaway, but solid waste is discharged into the case, causing various problems. The battery module has a lead plate connection arm positioned opposite the bottom of the cylindrical battery can, but the connection arm cannot prevent the solid waste from passing through the bottom valve, passing through the lead plate and being discharged into the case, causing various problems. The lead plate cannot prevent the solid waste from passing through because the connection arm has a cantilever structure with one end stacked on the lead plate, and is deformed by the solid waste being forcefully discharged.

[0028] Below, we will describe in detail a battery module in which a lead plate that can prevent the passage of solid waste that is forcefully ejected from an open bottom valve is connected to the bottom of a cylindrical battery with a bottom valve.

[0029] (Embodiment 1) A battery module according to one embodiment of the present invention is shown in Figures 1 to 5. Figure 1 is a perspective view of a battery module 100, Figures 2 and 3 are enlarged perspective and cross-sectional views of the battery module 100 shown in Figure 1, and Figures 4 and 5 are enlarged plan and vertical cross-sectional views of the battery module shown in Figure 2. The battery module 100 shown in these figures comprises a battery unit 4 made up of multiple cylindrical batteries 1 and lead plates 3 connected to the cylindrical batteries 1 and connecting adjacent cylindrical batteries 1 in series or parallel, and this battery unit is housed in an exterior case 5.

[0030] [Cylindrical battery 1] The cylindrical battery 1 is preferably a non-aqueous electrolyte battery such as a lithium ion battery. Because lithium ion batteries have a large capacity relative to their weight and capacity, a battery module 100 using lithium ion batteries as cylindrical batteries 1 can be made smaller and lighter while increasing charge / discharge capacity. However, the present invention does not limit the cylindrical battery 1 to a non-aqueous electrolyte battery, and other cylindrical batteries 1 equipped with a can bottom valve that opens when the internal pressure rises to a threshold pressure can also be used.

[0031] As shown in the enlarged cross-sectional view of Figure 5 and the perspective view of Figure 6, the cylindrical battery 1 is equipped with a can bottom valve 16 that opens when the internal pressure of the outer can 11 increases. The can bottom valve 16 opens to discharge the high-temperature contents when the internal pressure exceeds a threshold pressure due to thermal runaway or other reasons. The high-temperature discharge from the open can bottom valve 16 is a mixture of exhaust gas and solid waste. It is important that the exhaust gas be smoothly passed through the lead plate 3 and discharged. A lead plate 3 that does not allow the exhaust gas to pass smoothly would essentially close the opening of the can bottom valve 16, increasing the internal pressure of the cylindrical battery 1 and compromising the safety of the cylindrical battery 1. The lead plate 3 is required to allow the exhaust gas to pass through smoothly while preventing the passage of solid waste. If solid waste passes through the lead plate 3, it will enter between the lead plate 3 and the battery case 2, causing various problems. For example, if solid waste passes through the lead plate 3 and comes into contact with the exposed conductive portion, an excessive short-circuit current will flow inside, which will compromise safety.

[0032] As shown in FIG. 5, the cylindrical battery 1 contains a spiral electrode 20 made by laminating positive and negative electrode plates 21 with separators 22 between them, housed in a metal battery can 10, and filled with an electrolyte. The battery can 10 has a cylindrical outer can 11 whose bottom 12 is closed by a bottom plate 11A, and the opening is sealed with a sealing plate 13. The sealing plate 13 is insulated and airtightly fixed to the outer can 11 via an insulating material 14. The cylindrical battery 1 has electrodes 15 on both ends in the longitudinal direction. In the cylindrical lithium-ion battery 1, the protruding electrode 15A on the sealing plate 13 serves as the positive electrode, and the bottom electrode 15B on the bottom plate 11A of the outer can 11 serves as the negative electrode. The cylindrical battery 1 is a lithium-ion battery commonly known as an "18650" battery with a diameter of 18 mm and a total length of 65 mm, or a battery with these dimensions. Lithium-ion batteries close to or larger than the legal size can be used.

[0033] Cylindrical battery 1 connects spirally wound electrode 20 to protruding electrode 15A of sealing plate 13 and bottom electrode 15B of bottom plate 11A via internal tab 23. Internal tab 23, which connects bottom electrode 15B to spiral electrode 20, can be strong enough to break when can bottom valve 16 is open. This internal tab 23 is made of a metal plate or foil that is thinner than bottom plate 11A, or a thin conductor. In the cylindrical battery 1 shown in the cross-sectional view of Figure 5, internal tab 23 is connected by welding to the center of bottom plate 11A.

[0034] The internal tab 23, which breaks when the can bottom valve 16 is in an open state, allows the can bottom valve 16 to open particularly widely. However, the internal tab 23 does not necessarily have to have the strength to break when the can bottom valve 16 is in an open state. The internal tab 23 that does not break is pulled and deformed by the opening can bottom valve 16. In particular, because the internal tab 23 is connected to the can bottom valve 16 in a state of some slack, even when it is not broken, it is stretched linearly when the can bottom valve 16 is in an open state, thereby increasing the opening degree of the can bottom valve 16.

[0035] The can bottom 12 of the cylindrical battery 1 has an annular thinned line 17 that ruptures at a threshold pressure. The cylindrical battery 1 in FIG. 6 has a continuous, circular thinned line 17 to form a can bottom valve 16. When the can bottom valve 16 is opened, the entire thinned line 17 ruptures, allowing for a wide opening. However, the can bottom valve does not necessarily have to have a continuous, circular thinned line. As shown in FIGS. 7 and 8, a portion of the can bottom valve can be connected to the can bottom 12, with a non-connected portion 18 serving as a hinge portion 25. Because the hinge portion 25 of this can bottom valve 16 is connected to the bottom plate 11A, the thinned line 17 ruptures, deforming the hinge portion 25 and opening the valve. The cylindrical battery 1 shown in the perspective view of FIG. 7 and the plan view of FIG. 8 has a C-shaped thinned line 17 concentric with the circular can bottom 12, forming a loop-shaped thinned line 17 with a non-connected portion 18. In the cylindrical battery 1 shown in the figures, the loop-shaped thin-wall line 17 with the non-connecting portion 18 is C-shaped, but the thin-wall line 17 is not limited to this shape and can be, for example, a horseshoe shape, a U-shape, or a shape with ribs that approach each other at the tip of the U-shape. The can bottom valve 16 has a width wider than the width of the hinge portion 25, in other words, the width (D) of the can bottom valve 16 is wider than the distance (d) between the non-connecting portions 18, making it easier to open when the thin-wall line 17 breaks and increasing the opening area when the valve is open.

[0036] The threshold pressure at which the thin wall line 17 ruptures to open the can bottom valve 16 is determined by the material of the outer can 11 and the thickness of the thin wall line 17. For an outer can 11 made of steel, the thickness of the thin wall line 17 is set to, for example, 30 μm to 100 μm. The outer can 11 has the can bottom valve 16 formed by pressing the can bottom 12 to form a loop-shaped thin wall line 17 with a non-connected portion 18.

[0037] The can bottom 12 shown in the cross-sectional view of FIG. 5 is formed by pressing the can bottom 12 to form a thin line 17. The can bottom 12 in this figure has a flat surface 19 between the thin line 17 and the outer periphery of the can bottom 12, and the cross-sectional shape of the thin line 17 is a U-shaped curve that protrudes inward from the outer can 11. The can bottom valve 16 is pressed into a conical shape, with a chevron-shaped inward protrusion at its center. Furthermore, the boundary between the can bottom valve 16 and the thin line 17 protrudes outward beyond the flat surface 19 on the outer periphery of the can bottom 12. An internal tab 23, which is connected to a spiral electrode 20, is connected to the center of the can bottom valve 16, i.e., the chevron-shaped protrusion. The conical can bottom valve 16 is less likely to distort when internal pressure is applied, ensuring that the entire thin line 17 breaks and the valve can be opened wide.

[0038] Furthermore, although not shown, the cylindrical battery may be provided with a can bottom valve at the bottom of the outer can and a vent valve on the sealing plate that closes the opening of the outer can. This battery module quickly vents exhaust gases through the can bottom valves and vent valves provided at both ends of the cylindrical battery, more effectively suppressing an increase in internal battery pressure.

[0039] [Lead plate 3] The lead plates 3 are elastically deformable metal plates made of nickel, copper, or an alloy of these, and are arranged facing both end faces of multiple cylindrical batteries 1, which are arranged parallel to each other with both end faces on the same plane. The battery module 100 in Figure 5 has a pair of lead plates 3 arranged horizontally above and below the cylindrical battery 1 in the figure. The pair of lead plates 3 are arranged on the side facing the can bottom 12 of the cylindrical battery 1 and the side facing the sealing plate 13, and are electrically connected to the protruding terminal 15A on the sealing plate 13 and the bottom electrode 15B on the can bottom 12, connecting adjacent cylindrical batteries 1 in series or parallel.

[0040] The lead plate 3, which is disposed opposite the can bottom side, has a double-supported arm 31 connected to the lead plate 3 at both ends at a position opposite the can bottom valve 16, and gas permeation gaps 32, which allow exhaust gas to pass through, are provided on both sides of the double-supported arm 31. Furthermore, the lead plate 3 shown in the figure has connecting arms 33 welded to the can bottom 12 on both sides of the double-supported arm 31, and a gas permeation gap 32 is provided between the double-supported arm 31 and the connecting arm 33. In addition, in battery packs that carry large currents, lead plates alone may not be able to tolerate large current values. In such cases, a component called a current collector, which has a similar shape to the lead plate, may be attached to the lead plate to increase the allowable current value. This current collector can also have the same mechanism as the lead plate.

[0041] [Double-arm 31] The arms 31 support both ends and prevent the passage of solid matter discharged from the can bottom valve 16, while the gas permeation gap 32 allows the passage of discharge gas. In the lead plate 3 shown in Figures 3 to 5 and 8, the arms 31 support both ends and are positioned so as to extend in the diameter direction of the circular can bottom 12, with the arms 31 facing each other with the circular can bottom 12 at the center.

[0042] The double-supported arm 31 has a strength sufficient to prevent solid waste contained in the high-temperature, high-pressure waste discharged from the can bottom valve 16 from colliding with its inner surface and breaking it; for example, the width (W1) at its narrowest region is 1 mm or more, preferably 1.2 mm or more, and more preferably 1.5 mm or more. The double-supported arm 31 in Figures 4 and 8 has a wide base width (W2) on one side (the lower side in the figures) and both ends of the base on the opposite side are cut into a curved shape on the inside to narrow the width (W1). As shown in the figures, the lead plate 3 having a wide width (W2) on one side to provide a wide portion 31A has the advantage of being able to more reliably block the passage of solid waste that collide with the inner surface of the wide portion 31A. 8, in particular, the thinning line 17 is C-shaped rather than a continuous loop, as shown by the chain line in the figure, which more reliably prevents solid waste discharged from the can bottom valve 16, which is partially connected to the can bottom 12 and has the non-connected portion 18 as a hinge portion 25, from passing through the lead plate 3. This is because by providing the hinge portion 25 of the can bottom valve 16 at the end opposite the wide portion 31A, waste spurting from the open can bottom valve 16 is directed onto the inner surface of the wide portion 31A, which more reliably prevents solid waste from passing through the lead plate 3. However, the shape of the double-supported arm 31 in the present invention is not limited to the shape shown in the figure. For example, although not shown, it may be a double-supported arm with the same width, or a double-supported arm that gradually widens toward both ends.

[0043] [Gas permeation gap 32] The gas permeation gap 32 is provided on both sides of the double-supported arm 31, between the connecting arm 33. The gas permeation gap 32 is set to a width that allows gas components contained in the exhaust, i.e., exhaust gas, to pass through but does not allow solid exhaust to pass through. The lead plate 3 in FIG. 5 has the gas permeation gap 32 in the form of a slit with an opening width (K) that does not allow solid exhaust to pass through. The gas permeation gap 32 is set, for example, so that the opening width (K) of its widest region in cross section is 5 mm or less, preferably 3 mm or less, so that solid exhaust of a size that would cause adverse effects if it passes through the lead plate 3 does not pass through. If the gas permeation gap 32 is too large, large solid exhaust will pass through, but if it is too narrow, exhaust gas will not pass through smoothly, so it is preferably set to be wider than 1 mm.

[0044] [Connecting arm 33] 4, 5, and 8, the lead plate 3 has a connecting arm 33 on both sides of a double-supported arm 31, and a gas-permeable gap 32 is provided between the double-supported arm 31 and the connecting arm 33, so that the gas-permeable gap 32 is provided on both sides of the double-supported arm 31. The connecting arm 33 is a cantilevered arm that is connected at one end to the lead plate 3. connection The arms have their tips welded to the can bottom 12, electrically connecting the lead plate 3 to the can bottom 12. The cantilevered connection arms 33 are welded to the outer periphery of the can bottom 12 outside the annular thinning line 17. With this structure, when the thinning line 17 breaks and the can bottom valve 16 opens, the pair of connection arms 33 position the lead plate 3 in a fixed position on the can bottom 12, preventing the both-end supported arms 31 from shifting position and positioning them in a fixed position, so that the both-end supported arms 31 can reliably prevent the permeation of solid waste.

[0045] As shown in Figures 3 and 5, the lead plate 3 is positioned away from the can bottom surface, and the connecting arm 33 is deformed so that its tip contacts the can bottom 12 and is welded to the can bottom 12. The double-supported arm 31 is positioned flush with the lead plate 3 and positioned away from the can bottom 12, and the connecting arm 33 has its tip contacting and welded to the can bottom 12. The lead plate 3 connected to the can bottom 12 of the cylindrical battery 1 in this state has a step between the double-supported arm 31 and the connecting arm 33, making the effective opening area of ​​the gas permeation gap 32 larger than the opening area of ​​the lead plate 3 in a plan view, allowing exhaust gas to pass through more smoothly. In addition, exhaust gas ejected from the open can bottom valve 16 collides with the inner surface of the double-supported arm 31, changes direction of flow horizontally, and passes through the step gap between the double-supported arm 31 and the connecting arm 33, preventing exhaust gas that has passed through the lead plate 3 from directly colliding vertically with the inner surface of the outer case 5. This effectively prevents thermal damage to the exterior case 5 caused by high-temperature exhaust gases that have passed through the lead plate 3. [Industrial Applicability]

[0046] The present invention is a battery module made up of cylindrical batteries connected by metal lead plates, and is particularly suitable for use as a battery module including cylindrical batteries with a can bottom valve that ruptures to open a discharge port when the internal pressure of the outer can becomes too high. [Explanation of symbols]

[0047] 100...Battery module 1...Cylindrical battery 2. Battery case 3...Reed plate 4. Battery unit 5...Outer case 10...Battery can 11...Outer can 11A...Bottom plate 12...Bottom of can 13...Sealing plate 14...Insulating material 15...Electrode 15A...Convex electrode 15B…Bottom electrode 16...Can bottom valve 17...Thin-wall line 18…Unconnected part 19...Plane part 20...Spiral electrode 21...electrode plate 22...Separator 23...Internal tab 25...hinge part 31...Double-arm 31A...Wide section 32...Gas permeation gap 33...Connecting arm

Claims

1. a plurality of cylindrical batteries; lead plates connected to the cylindrical batteries to electrically connect the cylindrical batteries together; A battery module comprising: The cylindrical battery is a can bottom valve formed of a thin-walled line that ruptures to open a discharge port when the internal pressure of the outer can exceeds a threshold pressure; The lead plate is a double-supported arm disposed opposite the can bottom valve of the can bottom of the cylindrical battery; a gas permeation gap for exhaust gas ejected from the exhaust port on both sides of the double-supported arm; A battery module comprising:

2. The battery module according to claim 1, The battery module is characterized in that the arms are arranged so as to extend in the diameter direction of the circular can bottom.

3. The battery module according to claim 1 or 2, the lead plate has connecting arms welded to the can bottom on both sides of the double-supported arm, The gas permeable gap is provided between the both-end supported arm and the connecting arm, and further The battery module is characterized in that the connection arm is a cantilevered connection arm having one end connected to the lead plate and a tip welded to the bottom of the can.

4. The battery module according to claim 3, The battery module is characterized in that the cantilevered connecting arm is welded to the can bottom outside the annular thin-wall line.

5. The battery module according to any one of claims 1 to 4, The cylindrical battery is A battery module, characterized in that the can bottom valve is provided on both the bottom of an outer can and a sealing plate that closes the opening of the outer can.

6. The battery module according to any one of claims 1 to 5, The battery module is characterized in that the width of the double-supported arm is 1.5 mm or more.

7. The battery module according to any one of claims 1 to 6, The battery module is characterized in that the gas permeation gap has an opening width (K) of 5 mm or less in a vertical cross-sectional view.

8. The battery module according to any one of claims 1 to 7, The battery module is characterized in that the cylindrical batteries are non-aqueous electrolyte secondary batteries.

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