Power supply device

Abstract

This power supply device is provided with: a plurality of battery cells in which a plurality of electrode terminals are arranged; a battery holder which arrange the plurality of battery cells in fixed positions; and a lead plate which is fixed to the plurality of electrode terminals of the plurality of battery cells and is made of metal. The plurality of battery cells respectively have first end surfaces. Among the plurality of electrode terminals, each one of the electrode terminals is disposed on a corresponding one of the first end surfaces of the plurality of battery cells. The lead plate has: a base part; a fixed terminal which is connected to a corresponding one of the electrode terminals among the plurality of electrode terminals of the plurality of battery cells; and a fuse link which links the base part and the first fixed terminal and has a width narrower than that of the first fixed terminal. The battery holder has an end surface plate which covers the first end surfaces of the plurality of battery cells. The end surface plate has a plurality of electrode windows which expose respectively at least a portion of the plurality of electrode terminals. The lead plate is connected to the plurality of electrode terminals through the plurality of electrode windows. The end surface plate has a first region on the outer periphery side and a second region which is inside the first region and is arranged in a position close to the electrode terminal side. The base part of the lead plate is opposed to the first region of the end surface plate and the fixed terminal of the lead plate is fixed to at least one of the plurality of electrode terminals in a state where the fuse link of the lead plate is disposed in the second region of the end surface plate.

Description

power supply

[0001] The present invention relates to a power supply device in which multiple battery cells are arranged in fixed positions in a battery holder and connected in series and / or parallel by lead plates, and in particular to a power supply device in which the lead plates are provided with fuse links that melt when the battery overcurrent occurs.

[0002] Power supplies that connect multiple batteries in series or parallel with lead plates use fuse links on the lead plates to prevent battery overcurrent (see Patent Documents 1 and 2). The lead plates are made of metal and connect the batteries in series or parallel, and are manufactured, for example, by cutting a single metal plate. The lead plates connect a base portion that connects the batteries in series or parallel to a fixed terminal that is connected to the battery's electrode terminal with a fuse link. Because the fixed terminal is connected to the base portion via the fuse link, the lead plate is designed to blow when the battery current, i.e., the current flowing through the fixed terminal, exceeds a set current. The set current at which the fuse link blows can be adjusted by the fuse link's electrical resistance, so fuse links made of metal with high conductivity are made thin to adjust the set current. The fuse link is made thin to increase its electrical resistance so that it generates heat and blows when a set overcurrent flows.

[0003] JP 2015-141801 A JP 2016-066455 A

[0004] Tolerances arising from components such as battery cells and battery holders, as well as manufacturing processes, cannot be reduced to zero. Due to the respective height tolerances arising from components and manufacturing processes, the first region of the end plate is higher than the standard height without height tolerances, and the electrode terminal is lower than the standard height without height tolerances. This combination results in a height tolerance between the first region of the end plate and the electrode terminal (hereinafter referred to as a height tolerance) compared to the height difference between the first region of the end plate and the electrode terminal at each standard height without height tolerances. The height tolerance is maximized when the first region of the end plate is higher than the standard height without height tolerances and the electrode terminal is lower than the standard height without height tolerances. The base portion of the lead plate on the first region is fixedly connected to the electrode terminal via the fuse link and the fixed terminal. However, due to the height tolerance, the fixed terminal at the tip of the fuse link cannot reach the electrode terminal. Therefore, in order to weld the fixed terminal to the electrode terminal, the fixed terminal of the fuse link is pulled toward the electrode terminal during welding. 19 , the first region 921a of the end plate 921 of the battery holder 902 extends to the vicinity of the connection with the fixed terminal 931, supporting the fuse link 933, and large stress is concentrated locally in the vicinity of where the first region 921a supports the fuse link 933. The local stress concentration causes deformation or bending of the fuse link 933, and the fuse link 933, which is processed to be thin so that it melts at a set overcurrent, is prone to coming loose due to impact or vibration, and is prone to breaking or cutting, thereby reducing the functionality of the fuse in various applications and causing a decrease in the reliability of the power supply device.

[0005] Therefore, by reducing the height tolerance of each component and each manufacturing process of the first region of the end plate and the electrode terminal, the height difference tolerance can be reduced, and local stress concentration in the fuse link can be reduced. However, reducing the height tolerance and height difference tolerance increases the cost of each component and each assembly and manufacturing cost, and can also cause problems such as reduced productivity due to increased assembly and manufacturing time and effort.

[0006] A power supply device according to one aspect of the present disclosure includes a plurality of battery cells each having a plurality of electrode terminals arranged thereon, a battery holder that arranges the plurality of battery cells in fixed positions, and a lead plate made of metal and fixed to the plurality of electrode terminals of the plurality of battery cells, wherein each of the plurality of battery cells has a first end surface, and a corresponding one of the plurality of electrode terminals is arranged on the first end surface of each of the plurality of battery cells, and the lead plate includes a base portion, a fixed terminal connected to the corresponding one of the plurality of electrode terminals of the plurality of battery cells, and a fuse link that connects the base portion and the first fixed terminal and has a width narrower than that of the first fixed terminal, and the battery holder the battery cell includes an end plate covering the first end faces of the plurality of battery cells, the end plate having a plurality of electrode windows that expose at least a portion of each of the plurality of electrode terminals, the lead plates being connected to the plurality of electrode terminals via the plurality of electrode windows, the end plate having a first region on the outer periphery and a second region that is located inside the first region and close to the electrode terminals, the base portion of the lead plate facing the first region of the end plate, and the fixed terminal of the lead plate being fixed to at least one of the plurality of electrode terminals with the fuse link of the lead plate being located on the second region of the end plate.

[0007] The power supply device described above has the advantage that it can prevent localized stress concentration on the fuse link and prevent deterioration of the fuse function without increasing costs.

[0008] 1 is a schematic perspective view of a power supply device according to a first embodiment. FIG. 2 is a schematic exploded perspective view of the power supply device shown in FIG. 1. FIG. 3 is a schematic exploded perspective view of the power supply device shown in FIG. 2. FIG. 4 is a schematic perspective view showing a lead plate, an end plate, and a battery cell. FIG. 5 is a schematic cross-sectional view of an example of an electrode terminal. FIG. 6 is a schematic cross-sectional view of a lead plate. FIG. 7 is a schematic cross-sectional view of an end plate and a battery cell. FIG. 8 is a schematic cross-sectional view of an example of an inclined surface. FIG. 9 is a schematic cross-sectional view of another example of an inclined surface. FIG. 10 is a schematic cross-sectional view of a lead plate, an end plate, and a battery cell according to a second embodiment. FIG. 11 is a schematic cross-sectional view of an example of a stepped surface. FIG. 12 is a schematic cross-sectional view of another example of a stepped surface. FIG. 13 is a schematic cross-sectional view of another example of a stepped surface. FIG. 14 is a schematic cross-sectional view of a lead plate, an end plate, and a battery cell according to a comparative example.

[0009] Embodiments of the present invention will be described below with reference to the drawings. However, the embodiments described below exemplify power supply devices embodying the technical concepts of the present invention, and the present invention does not limit the power supply device to the following. Furthermore, this specification in no way limits the components described in the claims to the components of the embodiments. The dimensions, materials, shapes, and relative locations of components described in the embodiments, unless otherwise specified, are not intended to limit the scope of the present invention and are merely illustrative examples. Note that the size and relative positions of components shown in the drawings may be exaggerated for clarity. Furthermore, in the following description, the same names and symbols indicate identical or similar components, and detailed descriptions will be omitted as appropriate. Furthermore, the elements constituting the present invention may be configured with the same component, with one component serving multiple functions, or conversely, the functions of one component may be shared by multiple components. In this disclosure, the up-down direction indicates the axial direction of the battery cell.

[0010] The present disclosure may be characterized by the following aspects.

[0011] A power supply device according to one embodiment of the present disclosure includes a plurality of battery cells, each having a plurality of electrode terminals arranged thereon, a battery holder that arranges the plurality of battery cells in fixed positions, and a lead plate made of metal and fixed to the plurality of electrode terminals of the plurality of battery cells, wherein each of the plurality of battery cells has a first end surface, and a corresponding one of the plurality of electrode terminals is arranged on the first end surface of each of the plurality of battery cells, and the lead plate has a base portion, a fixed terminal connected to the corresponding one of the plurality of electrode terminals of the plurality of battery cells, and a fuse link that connects the base portion and the first fixed terminal and has a width narrower than that of the first fixed terminal, and the battery holder has an end plate covering the first end face of each of the plurality of battery cells, the end plate having a plurality of electrode windows that expose at least a portion of each of the plurality of electrode terminals, the lead plates being connected to the plurality of electrode terminals via the plurality of electrode windows, the end plate having a first region on the outer periphery and a second region that is located inside the first region and close to the electrode terminals, the base portion of the lead plate facing the first region of the end plate, and the fixed terminal of the lead plate being fixed to at least one of the plurality of electrode terminals with the fuse link of the lead plate being located on the second region of the end plate.

[0012] The above configuration has the advantage of preventing localized stress concentrations on the fuse link and reducing fuse performance without increasing costs. By positioning the fuse link on the second region, which is closer to the electrode terminal than the first region, the fuse link does not come into contact with the first region of the battery holder end plate. This prevents large localized stress concentrations on the fuse link that would result from contact with the first region, thereby preventing reduction in fuse performance. Furthermore, the extremely simple structure of providing the end plate with the second region, positioned lower and closer to the electrode terminal than the first region, results in virtually no increase in cost.

[0013] In a power supply device according to another embodiment of the present disclosure, the second region may have a downwardly sloping surface from the connecting side connected to the first region toward the electrode terminal. This configuration has the advantage of being able to avoid local stress concentrations in the fuse link and prevent degradation of fuse function without increasing costs. By having the second region have a downwardly sloping surface from a portion of the first region, such as the connecting side connected to the first region, toward the electrode terminal, the contact area of ​​the fuse link, which is pulled toward the electrode terminal and tilts, with the second region is increased, thereby preventing and suppressing local stress concentrations in the fuse link. Furthermore, a simple structure in which the second region has a sloping surface hardly increases costs.

[0014] In a power supply device according to another embodiment of the present disclosure, the inclined surface can have an inclination angle that makes surface contact with the fuse link. The above configuration has the advantage of being able to prevent local stress concentrations on the fuse link and prevent degradation of fuse function without increasing costs. Surface contact refers to contact over a wider area than point or line contact. By having an inclination angle that allows the fuse link to make surface contact, the contact area with the fuse link, which tilts as it is pulled toward the electrode terminal, can be increased. By having an inclination angle that allows surface contact over a wide area extending in the longitudinal direction of the fuse link, local stress concentrations on the fuse link, which tilts as it is pulled toward the electrode terminal, can be avoided. Furthermore, a simple structure in which the inclined surface has an inclination angle that allows the fuse link to make surface contact, hardly increases costs.

[0015] In another embodiment of the power supply device according to the present disclosure, the inclination angle of the inclined surface on the base side of the second region can be smaller than that on the fixed terminal side. This configuration has the advantage of preventing local stress concentrations on the fuse link and reducing fuse function without increasing costs. By making the inclination angle of the inclined surface on the base side of the second region smaller than that on the fixed terminal side, the fuse link, which is pulled toward the electrode terminal and tilts, can make surface contact with the base side of the second region. The small contact area with the second region serves as a fulcrum, preventing local stress concentrations on the fuse link. For example, the inclination angle of the inclined surface can be gradually increased from the base side to the fixed terminal side, or the inclined surface can be made into a smooth curve. This allows the fuse link to gradually contact the base side of the second region, expanding the contact area and preventing or reducing local stress concentrations on the fuse link. Furthermore, a simple structure with different inclination angles hardly increases costs. The base side indicates the base side where the fuse link connects to the base side (the connecting side where the second region connects to the first region), and the fixed terminal side indicates the side closer to the fixed terminal than the base side (the side closer to the electrode terminal).

[0016] In a power supply device according to another embodiment of the present disclosure, the second region may have a stepped surface that is lower than the first region. The second region may also have one or more stepped surfaces with a difference in height. This configuration has the advantage of being able to avoid local stress concentration in the fuse link and prevent a deterioration in fuse function without increasing costs. The fuse link is disposed on the second region having a stepped surface that is lower than the first region. The difference in height between the first and second regions allows the second region, with which the fuse link tilts due to being pulled toward the electrode terminal, to be positioned lower toward the electrode terminal, thereby preventing local stress concentration in the fuse link. Furthermore, a non-contact region can be formed in which the tilting fuse link does not contact the second region. Furthermore, this simple structure, in which the second region has a stepped surface that is lower than the first region and has one or more stepped surfaces with a difference in height, hardly increases costs.

[0017] In a power supply device according to another embodiment of the present disclosure, the second region can have a contact portion with which the fuse link comes into contact. The above configuration has the advantage that, by having the second region have a contact portion with which the fuse link, which is pulled toward the electrode terminal and tilts, can prevent local stress concentration on the fuse link without increasing costs.

[0018] In another embodiment of the power supply device according to the present disclosure, the battery holder has a non-contact area on the second region where the fuse link does not contact the second region. This configuration has the advantage of preventing local stress concentrations on the fuse link without increasing costs. The non-contact area between the end plate and the second region ensures that the non-contact area does not contact the second region even when the fuse link is pulled downward due to a height difference intersection. Furthermore, the second region, with which the tilting fuse link makes contact, can be positioned lower, closer to the electrode terminal, preventing local stress concentrations on the fuse link. Furthermore, the non-contact area can be formed simply by locating the second region, with little increase in cost.

[0019] In another embodiment of the power supply device according to the present disclosure, the height difference between the first and second regions of the end plate can be 0.1 mm or more and 3 mm or less. This configuration has the advantage that, within the height difference range between the first and second regions of the end plate, the fuse link on the second region does not contact the second region, thereby preventing local stress concentration on the fuse link without increasing costs. The height difference between the first and second regions refers to the difference in height between the first region and the second region and indicates how much lower the second region is located than the first region. Here, the height of the first region is the height of the top of the first region. The height of the second region is based on the position of the second region that first comes into contact with a fuse link positioned at a predetermined position or tilted from a predetermined position.

[0020] In another embodiment of the power supply device according to the present disclosure, the height difference between the first and second regions of the end plate can be greater than the maximum height difference tolerance between the first region and the electrode terminal. The above configuration, by making the height difference between the lowest positions of the first and second regions of the end plate greater than the maximum height difference tolerance between the first region and the electrode terminal, can accommodate even maximum height difference tolerances between the first region and the electrode terminal, and has the advantage of preventing stress concentration on the fuse link without increasing costs. The maximum height difference tolerance between the first region and the electrode terminal is calculated by adding the absolute values ​​of the amount by which the first region is higher than a standard position without intersections (height tolerance of the first region) and the amount by which the electrode terminal is lower than a standard position without intersections (lowering tolerance of the electrode terminal) due to the tolerances of each component and manufacturing process of the power supply device, including the battery cell and battery holder.

[0021] In a power supply device according to another embodiment of the present disclosure, the battery cell may have an electrode terminal with a recessed portion on the first end face. This configuration has the advantage that stress concentration on the fuse link can be avoided and deterioration of fuse function can be prevented with almost no increase in cost, even when the center electrode of the battery cell is recessed, which is prone to localized stress concentration on the fuse link due to a large difference in elevation.

[0022] In a power supply device according to another embodiment of the present disclosure, multiple lead plates can be arranged on the first end face side of the battery cell. The above configuration has the advantage that by arranging multiple lead plates, localized stress concentrations occurring in the fuse link can be prevented with almost no increase in cost.

[0023] In another embodiment of the power supply device according to the present disclosure, the fuse link has a curved portion on the first end face, and the curved portion can be arranged along the outer periphery of the electrode window. The above configuration has the advantage that the curved portion can increase the longitudinal length of the fuse link compared to a straight line, thereby increasing the contact area of ​​the fuse link with the second region and contributing to suppressing local tilting of the fuse link, thereby preventing local stress concentration on the fuse link with almost no increase in cost. Furthermore, the first end face can be effectively utilized, contributing to the miniaturization of the power supply device.

[0024] In a power supply device according to another embodiment of the present disclosure, the fuse link has an arc portion that is positioned within the outer periphery of the first end face of the battery cell, and the arc portion can be positioned to surround the central axis of the battery cell. The above configuration has the advantage that the fuse link has an arc-shaped or elliptical arc portion that is positioned within the outer periphery of the first end face of the battery cell, making effective use of the first end face and preventing local stress concentration on the fuse link with almost no increase in cost. This also contributes to the miniaturization of the power supply device.

[0025] (Embodiment 1) Figures 1 to 12 show a power supply device 100 according to Embodiment 1 of the present invention. The power supply device 100 shown in Figures 2, 3, and 5 comprises a plurality of battery cells 1 that can be charged, a battery holder 2 that arranges the plurality of battery cells 1 in fixed positions, and lead plates 3 that electrically connect the plurality of battery cells 1 arranged in fixed positions by the battery holder 2. The power supply device 100 shown in Figures 1 and 2 is assembled by housing the battery holder 2, which arranges the plurality of battery cells 1 in fixed positions, in an exterior case 5. The battery holder 2 arranges the plurality of battery cells 1 in fixed positions with their ends aligned in the same plane, parallel to each other.

[0026] The power supply device 100 of the present disclosure has a fuse link 33 provided on a lead plate 3, and is used, for example, as a power source for motive power, for motor-driven electric devices such as power tools, power-assisted bicycles, electric motorcycles, electric wheelchairs, electric tricycles, and electric carts. However, the present invention does not specify the use of the power supply device, and it can be used as a power source for various electric devices used indoors and outdoors, other than electric devices, such as cleaners, radios, lighting devices, digital cameras, and video cameras.

[0027] (Battery Cell 1) The power supply device 100 includes multiple battery cells 1. In the power supply device 100 of Figure 5, the battery cells 1 are cylindrical batteries 1A. A cylindrical battery 1A has an electrode assembly housed in a cylindrical outer can, filled with electrolyte, and the opening of the outer can sealed with a sealing plate. The cylindrical battery 1A has positive and negative electrode terminals 11 on the bottom of the outer can, which are both end faces, and on the protruding electrodes located in the center of the sealing plate. Cylindrical batteries 1A with positive and negative electrode terminals 11 on both end faces are placed parallel to the battery holder 2, with the electrode terminals 11 exposed on both sides of the battery holder 2 and electrically connected via lead plates 3. While the power supply device 100 of Figure 5 uses cylindrical batteries 1A as the battery cells 1, this disclosure does not limit the battery cells 1 to cylindrical batteries 1A; for example, prismatic batteries are also possible. The battery cells 1 are nonaqueous electrolyte secondary battery cells, such as lithium-ion batteries. However, the present disclosure does not limit the battery cell 1 to a lithium ion battery, and all secondary batteries currently in use and those to be developed in the future, such as other non-aqueous electrolyte secondary batteries and nickel-metal hydride batteries, can be used.

[0028] The battery cell 1 has an electrode terminal 11 disposed on a first end surface 13. The first end surface 13 is at least one end surface of the battery cell 1. The battery cell 1 has the electrode terminal 11 on one or both end surfaces. The battery cell 1 shown in Figures 5 and 6 has a central electrode 12 disposed on the central axis and in the center of the first end surface 13 around the central axis. The battery cell 1 may have the central electrode 12 as one electrode and an electrode disposed in a peripheral portion other than the central portion or on the bottom surface, which is the end surface opposite the central portion, as the other electrode. The electrode terminal 11 may be a recessed electrode 12a having a recessed shape in a portion of the first end surface 13, an end surface electrode 12b having a substantially flat first end surface 13 with the same height, or a protruding electrode 12c having a protruding portion of the first end surface 13. The height of the first end surface 13 is determined based on the standard height of the peripheral portion other than the central portion.

[0029] The battery cells 1 in Figures 5 and 6 have electrode terminals 11 recessed in portions of the first end surface 13. The battery cells 1 in Figures 5 and 6 have electrode terminals 11 (recessed electrodes 12a) recessed in the center of the first end surface 13. As shown in Figure 7, in all cases of recessed electrodes 12a (dashed lines), end surface electrodes 12b (solid lines), and protruding electrodes 12c (dashed dotted lines), a height difference tolerance can occur between the first region 21a of the end surface plate 21 and the electrode terminal 11, which can result in stress concentration in the fuse link 33. In the case of the concave electrode 12a, the difference in height between the first region 21a and the electrode terminal 11 is greater than in the case of the end surface electrode 12b or the convex electrode 12c, and the tolerance for the difference in height between the first region 21a and the electrode terminal 11 is also greater. However, in the power supply device 100, the fuse link 33 of the lead plate 3 is positioned on the second region 21b, which is lower than the first region 21a of the end surface plate 21 and positioned closer to the electrode terminal 11. Therefore, even if a tolerance for the difference in height occurs between the first region 21a and the electrode terminal 11 and the fuse link 33 is pulled downward, there is no first region 21a with which the fuse link 33 comes into contact, and the position where the fuse link 33 comes into contact with the second region 21b is lowered, thereby preventing or reducing stress concentration on the fuse link 33.

[0030] The battery cell 1 in FIG. 3 has positive and negative electrode terminals 11 located on both end surfaces. In the battery cell 1 shown in the figure, the positive electrode terminal 11 is located on a center electrode 12 (recessed electrode 12a) in the center of the sealing plate, and the negative electrode terminal 11 is located on the bottom surface of the outer can, which is the end surface opposite the center electrode 12. However, this disclosure does not specify the structure of the battery cell 1 or the arrangement, shape, or configuration of the positive and negative electrode terminals 11. It applies to all battery cells having electrode terminals where there is an intersection (elevation difference intersection) between the first region 21a of the end plate 21 and the electrode terminal 11. For example, the positive and negative electrode terminals 11 can be located on one end surface of the battery cell 1, and the center electrode 12 can be a protruding electrode 12c or an end surface electrode 12b. The fixed terminal 31 (described later) is located according to the position of the electrode terminal 11 of the battery cell 1, and the shape, width, length, etc. of the fuse link 33 are appropriately determined.

[0031] (Lead Plates 3) The lead plates 3 are made of metal and electrically connect multiple battery cells 1. The lead plate 3 in Figure 3 connects multiple battery cells 1 in parallel. The lead plate 3 is fixed and connected to the electrode terminal 11 of each battery cell 1 via a fixed terminal 31. The fixed terminals 31 of the lead plates 3 are electrically connected and fixed to the electrode terminals 11 of the battery cells 1 by spot welding, laser welding, resistance welding, ultrasonic welding, or the like. The lead plates 3 in Figures 3 and 4 connect multiple battery cells 1 in parallel. The lead plate 3 in Figure 8 is made of conductive metal and has multiple fixed terminals 31 that are connected to the electrode terminals 11 of the battery cells 1, a base portion 32 that connects the multiple battery cells 1 via the fixed terminals 31, and a fuse link 33 that connects the fixed terminals 31 and the base portion 32. The fuse link 33 has a second end 33b on the base side (base 32 side) that connects to the base 32, and a first end 33a on the tip side (fixed terminal 31 side) that connects to the fixed terminal 31. The lead plate 3 is made by cutting and bending a single metal plate using a die. Figures 3 and 4 are schematic perspective views of the lead plates 3 arranged on the end plate 21 of the battery holder 2. The battery holder 2 in Figure 3 has ten lead plates 3 arranged thereon, connecting each battery cell 1 in parallel via the lead plates 3. The longitudinal ends of the multiple lead plates 3 on the top and bottom surfaces of the battery holder 2 are connected by multiple bus bars 4 arranged on both sides of the battery holder 2 to connect adjacent rows of battery cell 1 battery packs in series. However, although this disclosure shows a configuration in which multiple battery cells 1 are connected in parallel by lead plates 3, this is not limited to this, and multiple battery cells 1 may be connected in series or in both series and parallel by lead plates 3. Furthermore, this disclosure does not specify the shape, length, width, thickness, size, number, configuration, connection method, etc. of the lead plates, base portion, fixed terminals, and fuse links.

[0032] The base portion 32 is the remaining portion of the lead plate 3 excluding the fixed terminals 31 and fuse links 33, and constitutes the main body of the lead plate 3. The base portion 32 connects all battery cells 1 connected to the fixed terminals 31 in parallel and / or series. The lead plate 3 is formed by pressing a single metal plate, cutting it into a shape that accommodates multiple fixed terminals 31 and fuse links 33, and bending it. The base portions 32 are provided on the outside of the fixed terminals 31 and between adjacent fixed terminals 31. The base portion 32 in FIG. 8 is flat and is placed on the end plate 21. The base portion 32 is placed in contact with the first region 21a of the end plate 21, further covering the end plate 21 that covers the first end surface 13. The base portion 32 can be provided with a positioning portion for positioning the base portion 32 and a positional displacement prevention portion for preventing positional displacement, as necessary. For example, the base portion 32 in FIGS. 4 and 8 is provided with through holes 38 through which the positioning portions 28a and misalignment prevention portions 28b provided in the first region 21a are inserted, thereby achieving positioning and preventing misalignment.

[0033] The fixed terminal 31 is a fixing piece that electrically connects and secures the lead plate 3 to the electrode terminal 11 of the battery cell 1. The fixed terminal 31 is welded to the electrode terminal 11 of the battery cell 1 by spot welding, laser welding, or other welding methods. The fixed terminal 31 is located inside the electrode window 8 in the end plate 21 of the battery holder 2 and is welded to the electrode terminal 11 of the battery cell 1. The fixed terminal 31 in Figure 8 has a welded portion 31a, which is the welded part, and a stepped portion 31b. The upper end of the stepped portion 31b is connected to the first end 33a at the tip side of the fuse link 33, and the lower end is connected to the welded portion 31a, eliminating the step between them. The fixed terminal 31 has the welded portion 31a at the tip below the stepped portion 31b. 8 , the lead plate 3 is connected to the tip of the fuse link 33 via a stepped portion 31b of the fixed terminal 31 so that the welded portion 31a of the fixed terminal 31, which is disposed within the electrode window 8 of the end plate 21, can abut against the electrode terminal 11. That is, the lead plate 3 is provided with the stepped portion 31b on the fixed terminal 31, and the welded portion 31a is disposed in a stepped shape relative to the base portion 32. By providing the stepped portion 31b on the fixed terminal 31 in this manner, the fixed terminal 31, which protrudes downward (toward the electrode terminal 11) from the base portion 32 toward the electrode terminal 11, is inserted into the electrode window 8 of the end plate 21 and is connected in contact with the electrode terminal 11 disposed on the inner surface of the electrode window 8. A gap is provided between the fixed terminal 31 and the base portion 32, separating the welded portion 31a from the base portion 32. The welded portion 31a is located inside the electrode window 8 provided in the battery holder 2 and is connected to the electrode terminal 11 of the battery cell 1 by spot welding or the like. The fixed terminal 31 shown in Figure 8 is roughly rectangular with chamfered corners, but it can be other shapes and can also be provided with slits or the like. The power supply device 100 in Figure 5 connects the fixed terminal 31 to the electrode terminal 11 in the recessed part of the battery cell 1.

[0034] The fuse link 33 is a connecting arm that connects the base portion 32 and the fixed terminal 31. The width of the fuse link 33 in FIG. 8 is narrower than that of the fixed terminal 31. The lead plate 3 is connected to the base portion 32 and the fixed terminal 31 via the thin connecting arm fuse link 33. The fuse link 33 has a first end 33a on the tip side that is connected to the fixed terminal 31 via a step portion 31b, and a second end 33b on the base side that is connected to the base portion 32. The thin fuse link 33 generates heat and melts when a set overcurrent flows.

[0035] The fuse link 33 can be disposed entirely or partially on the first end surface 13. The fuse link 33 is preferably disposed within the outer periphery of the first end surface 13. The fuse link 33 provided for each battery cell 1 is shaped and disposed so as to fit within the first end surface 13 of the battery cell 1, thereby not overlapping the first end surface 13 of an adjacent battery cell 1 and contributing to the miniaturization of the power supply device 100.

[0036] The fuse link 33 can have a linear or curved shape extending in the longitudinal direction. The fuse link 33 in FIG. 8 has a curved portion 34 that curves inward toward the center (inward) of the battery cell 1. The curved portion is longer in the longitudinal direction than a fuse link 33 that extends linearly in the longitudinal direction, which helps prevent local stress concentration in the fuse link 33. Furthermore, the fuse link 33 in FIG. 8 has an inwardly curved portion that is arranged along the periphery of the electrode window 8. By arranging the curved portion of the fuse link 33 along the periphery of the electrode window 8, it can be arranged around the central axis of the battery cell 1, which contributes to the miniaturization of the power supply device 100 and also makes it easy to provide a gap of approximately equal width between the fuse link 33 and the base portion 32. The fuse link 33 in FIG. 8 has an arc-shaped or elliptical arc-shaped portion. By arranging the arc portion so as to surround the central axis of the battery cell 1, it is easy to provide a gap between the fixed terminal 31 and the base portion 32, and a fixed terminal 31 of a specified area and shape, which makes effective use of the area surrounding the central axis of the battery cell 1 and contributes to miniaturizing the power supply unit 100.

[0037] By connecting multiple lead plates 3, multiple battery cells 1 can be connected in series and parallel. Furthermore, the lead plate 3 provided on one or both end faces of the battery cell 1 can be configured with one or multiple lead plates 3. The multiple lead plates 3 can have different shapes, thicknesses, widths, sizes, and configurations. The power supply device 100 in FIG. 3 has lead plates 3 disposed on both the upper and lower end faces of the battery cell 1. Furthermore, in the power supply device 100, the lead plate 3 disposed on the first end face 13 can be configured by stacking multiple lead plates 3. For example, the lead plate 3 disposed on the first end face 13 can be configured by stacking a second lead plate on a first lead plate. For example, the thickness of the first lead plate disposed on the lower side (closer to the electrode terminal 11) can be thinner than the second lead plate disposed on the upper side (away from the electrode terminal 11). The first lead plate has a fuse link 33 and a fixed terminal 31, and is connected to the electrode terminal 11 via these fuse links 33 and fixed terminals 31. The relatively thin first lead plate can easily tilt when the fuse link 33 is pulled downward due to a height difference, thereby avoiding stress concentration. Furthermore, the thin first lead plate, along with the narrow width of the fuse link 33, increases the electrical resistance of the fuse link 33, allowing it to fuse at a predetermined set current. The relatively thick second lead plate reinforces the first lead plate with its thickness, and the increased thickness lowers the resistance of the entire lead plate 3, reducing and suppressing heat generation and power consumption. This configuration also allows the first and second lead plates to be made of metal plates of different thicknesses, reducing parts and manufacturing costs. However, the lead plate 3 can also be partially thinned.

[0038] (Battery Holder 2) As shown in the exploded perspective view of FIG. 3 and the cross-sectional view of FIG. 5, the battery holder 2 inserts multiple battery cells 1 into the battery storage compartment 6 and positions them in a parallel orientation. The battery holder 2 can be composed of, for example, a pair of holder units split in the middle. This holder unit connects end plates 21 to the end faces of the battery storage compartment 6 through which the battery cells 1 are inserted and held. The end plates 21 open electrode windows 8 that at least partially expose the electrode terminals 11 of the battery cells 1, and lead plates 3 connect to the electrode terminals 11 of the battery cells 1 exposed through these electrode windows 8. Battery cells 1 with positive and negative electrode terminals 11 on both end faces are placed in a parallel orientation in the battery holder 2, with the electrode terminals 11 at both ends exposed on both sides of the battery holder 2 and electrically connected by the lead plates 3. The shape of the electrode windows 8 is not particularly specified and can be, for example, approximately circular or approximately rectangular. The electrode window 8 is made smaller than the outer shape of the battery cell 1 so that the battery cell 1 does not pass through, and the battery cell 1 is housed in the battery housing section 6.

[0039] The battery holder 2 has a battery storage section 6 that stores a predetermined number of battery cells 1, and an end plate 21 that covers a first end surface 13 on which the electrode terminals 11 of the battery cells 1 are located. The battery cells 1 are inserted into the battery storage section 6, with the electrode terminals 11 on both end surfaces arranged flush and exposed on both sides of the battery holder 2. The battery holder 2 defines the battery storage section 6 with partitions 7. The partitions 7 are in thermally coupled contact with the outer surfaces of the battery cells 1. The partitions 7, thermally coupled to the battery cells 1, conduct and absorb heat generated by the battery cells 1. The partitions 7 that define the battery storage section 6 are located between adjacent battery cells 1, with their surfaces in thermal contact with the surfaces of the battery cells 1, and they position the battery cells 1 in place by contacting their surfaces. The battery storage compartments 6, which are separated by partitions 7, have inner surfaces that conform to the outer periphery of the battery cells 1, as battery cells 1 are inserted and positioned therein. The battery holder 2 in Figure 5 has cylindrical battery storage compartments 6, as cylindrical batteries 1A are inserted into the battery storage compartments 6 and positioned therein. The cylindrical battery storage compartments 6 have an inner diameter slightly larger than the outer diameter of the cylindrical batteries 1A, allowing them to be thermally coupled to and positioned in place. Because the battery storage compartments 6 are separated by partitions 7, the surfaces of the partitions 7, which are positioned between the battery cells 1, are shaped to conform to the surfaces of the cylindrical batteries 1A.

[0040] The end plate 21 has a first region 21a on the outer surface of the end plate 21 and a second region 21b located closer to the electrode terminal 11 than the first region 21a. In FIGS. 5, 6, and 9, the first region 21a is the upper surface region (outer region) of the end plate 21. The second region 21b is a middle surface located lower than the first region 21a in the axial direction of the battery cell 1. If the first region 21a has a different height, the second region 21b is located lower than the top of the first region 21a. The second region 21b can be located within the thickness of the end plate 21 and is provided between the top of the first region 21a (upper surface region) and the bottom of the third surface 21c (lower surface region). The second region 21b can have a thickness equal to or less than the height from the second region 21b to the third surface 21c. The third surface 21c can also have a different height. The second region 21b can determine the contact position and tilt range of the fuse link 33. The second region 21b has a certain thickness from the third surface 21c, so that it can support the tilted fuse link 33. The second region 21b has a predetermined thickness that can support the fuse link 33 when it comes into contact with it, and the thickness is set to an appropriate thickness depending on the shape, inclined surface, etc. of the second region 21b. However, the configuration below the second region 21b is not specified, and a reinforcing member such as a rib can be provided, for example. The second region 21b is provided at a predetermined position by connecting to the vertical surface, etc. of the end plate 21.

[0041] 19 is a power supply device 900 of the comparative example, in which a first region 921a of an end plate 921 is disposed up to near a first end 933a on the tip side of a fuse link 933. In the power supply device 900 of the comparative example, the fuse link 933 contacts the first region 921a of the end plate 921 at a position close to the first end 933a, and the fixed terminal 931 is pulled downward toward the electrode terminal 911 due to the difference in height, resulting in a localized large stress concentration in the fuse link 933 near the first end 933a. Specifically, stress concentrates in the fuse link 933 at the base (first end 933a) of the fixed terminal 931, which is not supported by the first region 921a of the end plate 921, inside (toward the central axis) of the contact point between the fuse link 933 and the first region 921a of the end plate 921, causing bending.

[0042] In contrast, the power supply device 100 prevents local stress concentration near the contact point between the fuse link 33 and the first region 21a by having the fuse link 33 pass through on the second region 21b, which is positioned closer to the electrode terminal 11 than the first region 21a. The second region 21b is positioned according to the shape of the fuse link 33 and is positioned in an area that at least covers the area below the fuse link 33. The power supply device 100 places the fuse link 33 on the second region 21b. "On the second region 21b" refers to a position above the second region 21b, and does not matter whether the fuse link 33 is in contact with the second region 21b. "On the second region 21b" includes cases where the fuse link 33 is in contact with the second region 21b and cases where it is not in contact with the second region 21b.

[0043] When the fuse link 33 disposed on the second region 21b does not contact the second region 21b, i.e., when the fuse link 33 is disposed at a position above and away from the second region 21b, the end plate 21 forms a non-contact region 25 between the fuse link 33 and the second region 21b. The non-contact region 25 is a region where the fuse link 33 does not contact the second region 21b. In FIG. 6 , the non-contact region 25 is a gap space surrounded by the fuse link 33 on the upper side and the second region 21b on the lower side. The existence of the non-contact region between the end plate 21 and the second region 21b ensures that the fuse link 33 does not contact the second region 21b even when the fuse link 33 is pulled downward due to the intersection of height differences. This also lowers the position where the fuse link 33 contacts the second region 21b, preventing stress concentration on the fuse link 33. FIG. 12 shows a state in which the fuse link 33 is pulled downward and tilts to contact the inclined surface 22 of the second region 21b. The inclined surface 22 in the figure has an inclination angle (θ) that brings the fuse link 33 into surface contact with the inclined surface 22, and the fuse link 33 makes contact with the inclined surface 22 over a wide contact area.

[0044] The second region 21b can have an inclined surface 22 that slopes in either direction. The second region 21b can be provided with an inclined surface 22 entirely or partially. The second region 21b in FIGS. 5 to 7 and 9 has an inclined surface 22 that slopes in the longitudinal direction of the fuse link 33. The inclination start position (upper end of the inclined surface 22) of the inclined surface 22 can be in the first region 21a (upper surface region) or at a position lower than the first region 21a, and the final position (lower end) of the inclined surface 22 can be in the third surface 21c (lower surface region) or at a position higher than the third surface 21c. FIGS. 10 and 11 are explanatory schematic cross-sectional views showing the second region 21b (inclined surface 22) as a straight line. The second region 21b may have, for example, an inclined surface 22 extending from the first region 21a to the third surface 21c, or an inclined surface 22 extending from the first region 21a to a position higher than the third surface 21c ( FIGS. 10 and 11 ), or an inclined surface extending from a position lower than the first region 21a to the third surface 21c or a position higher than the third surface 21c ( FIGS. 17 and 18 ). The second region 21b in FIGS. 5 to 7 and 9 has a downwardly sloping surface 22 (slope) extending from the first region 21a toward the electrode terminal 11. This inclined surface 22 allows the fuse link 33 to contact the electrode terminal 11 over a wide contact area, preventing localized stress concentration. The inclined surface 22 may have the same or different inclination angles (θ). For example, as shown in FIG. 10, the inclined surface 22 may have a constant inclination angle (θ). 11 , the inclination angle (θ1) between the first region 21a and the connecting side can be smaller than the inclination angle (θ2) of the final position side of the inclined surface 22 other than the first region 21a side or any portion between the first region 21a side and the final position side of the inclined surface 22. The inclination angle (θ) of the inclined surface 22 can be increased as the inclination angle approaches the final position side of the inclined surface 22 (e.g., FIG. 11 ). The inclined surface 22 can be smoothly curved by reducing the change in the inclination angle (θ) (e.g., FIG. 11 ). In either case, local stress concentration can be prevented by tilting the fuse link 33 while making surface contact with the inclined surface 22 of the second region 21b. Stress concentration of the fuse link 33 is likely to occur near the contact point where the lower surface of the fuse link 33 first comes into contact. However, by increasing the contact area between the fuse link 33 and the second region 21b of the inclined surface 22 and tilting the fuse link 33 while making surface contact, local stress concentration can be prevented.The inclined surface 22 has the contact portion 24 extending in the longitudinal direction of the fuse link 33, thereby making it possible to widen the contact area, and local stress concentration can be prevented by gradually increasing the tilt angle of the fuse link 33. For example, the inclined surface 22 in Fig. 12 has the contact portion 24 extending in the longitudinal direction of the fuse link 33, and shows a state in which the tilted fuse link 33 is in contact with the second region 21b of the inclined surface 22 over a wide contact area.

[0045] The inclined surface 22 has a surface that slopes in the direction in which the fuse link 33 tilts, allowing the inclination to match the tilt, thereby suppressing and preventing stress concentration. The inclined surface 22 preferably has an inclination angle (θ) that allows the tilted fuse link 33 to make surface contact. Surface contact refers to contact over a wider area than point contact or line contact. Surface contact can prevent local stress concentration more effectively than point contact or line contact. For example, by gradually increasing the inclination angle (θ) of the inclined surface 22 or by making the inclined surface 22 a smoothly curved surface, the contact area with the inclined surface 22 can be expanded as the fuse link 33 tilts. The surface contact of the fuse link 33 with the inclined surface 22 allows contact over an area extending in the longitudinal direction as well as the width direction of the fuse link 33, thereby more effectively suppressing and preventing local stress concentration.

[0046] The inclined surface 22 does not specify the direction of inclination. For example, the inclined surface 22 may entirely or partially have a surface inclined in the width direction of the fuse link 33. The fuse link 33 has an arc shape surrounding the central axis of the battery cell 1, and accordingly may entirely or partially have a surface inclined toward the central axis of the battery cell 1 or toward the outer periphery, which is the diameter direction of the battery cell 1. For example, by inclining the inclined surface 22 downward toward the central axis of the battery cell 1, the force that presses against the inclined surface 22 when the lower surface of the fuse link 33 comes into contact with it can be released in the downward inclination direction toward the central axis of the battery cell 1, effectively suppressing and preventing local stress concentration in the fuse link 33. In the case of an inclined surface 22 inclined downward toward the outer periphery, the vertical surface to which the second region 21b is connected on the outside of the fuse link 33 can define the tilt range of the fuse link 33 and support the tilted fuse link 33 at a predetermined position. Even in the case of an inclined surface 22 that slopes downward toward the central axis, the tilt range of the fuse link 33 can be defined, and the tilted fuse link 33 can be supported at a predetermined position, for example, by providing a guide on the central axis side or by reducing or eliminating the inclination angle in the perpendicular direction. The inclined surface 22 can be a flat surface, a curved surface, or a combination of a flat surface and a curved surface, and the inclined surface can also be provided with unevenness or steps.

[0047] The second region 21b may have a contact portion 24 with which the fuse link 33 comes into contact. In the case of an end plate 21 having a non-contact region 25, the contact portion 24 is the portion with which the tilted fuse link 33 comes into contact. The contact portion 24 is a portion that avoids local stress concentration in the fuse link 33, disperses stress, and guides the tilting of the fuse link 33. The contact portion 24 may be provided regardless of whether the non-contact region 25 is present. The contact portion 24 increases the contact area with the fuse link 33 and the number of contacts, thereby avoiding local stress concentration in the fuse link 33. For example, the contact portion 24 may have a shape, inclination angle, or inclined surface that allows the tilted fuse link 33 to make surface contact. The contact portion 24 may also be provided with an elastic body, or may have a tilting portion that can tilt together with the fuse link 33.

[0048] The thickness of the end plate 21 is, for example, 0.5 mm to 5 mm, preferably 1 mm to 4 mm. The maximum height difference between the first region 21a and the second region 21b is equal to or less than the thickness of the end plate 21. The height difference between the first region 21a and the second region 21b is, for example, 0.1 mm to 3 mm, preferably 0.5 mm to 2 mm. On the one hand, increasing the height difference between the first region 21a and the second region 21b can expand the range of height difference intersections that can be accommodated, and on the other hand, reducing the height difference between the first region 21a and the second region 21b can reduce the size of the power supply device 100. In the end plate 21, the height difference between the first region 21a and the second region 21b is greater than the maximum height difference tolerance between the first region 21a and the electrode terminal 11, thereby reliably preventing local stress concentration in the fuse link 33. This is because the height difference between the first region 21 a and the second region 21 b can absorb the maximum height difference tolerance between the first region 21 a and the electrode terminal 11. For example, if the height difference between the first region 21 a and the second region 21 b is set to 1 mm or more, the height difference tolerance between the first region 21 a and the surface of the electrode terminal 11 can be in the range of 0.1 mm to 1 mm, and local stress concentration in the fuse link 33 can be prevented.

[0049] The battery holder 2 is molded into a predetermined shape from an insulating resin such as a thermoplastic resin. The battery holder 2 is preferably made of a resin with excellent flame retardancy. Examples of such resins include polycarbonate (PC) and polypropylene (PP).

[0050] 13 to 18 show a power supply device 200 according to embodiment 2. In the power supply device 100 shown in the figures, the second region 21b has a sloped surface 22 that slopes downward from the first region 21a side toward the electrode terminal side. In contrast, in the power supply device 200 shown in the figures, the second region 21b has a stepped surface 23 that is lower than the first region 21a.

[0051] 13 and 14 is a step surface 23 that is located lower than the first region 21a. The second region 21b (step surface 23) is located closer to the electrode terminal side than the first region 21a, and is located lower than the first region 21a in Fig. 14. By making the second region 21b the step surface 23 that is located lower than the first region 21a, even if the fuse link 33 is pulled downward due to the intersection of the elevation difference and tilts, the first region 21a is not located in a position that would contact the fuse link 33, and the fuse link 33 is not located in contact with the second region 21b, which is located lower by the elevation difference between the first region 21a and the second region 21b, so that local stress concentration in the fuse link 33 can be prevented.

[0052] 15 to 18 are explanatory schematic cross-sectional views showing the second region 21b (e.g., the stepped surface 23) linearly. In FIG. 15, the stepped surface 23 of the second region 21b is positioned lower than the first region 21a (closer to the electrode terminal). The second region 21b can have one or more stepped surfaces 23 with different heights. The stepped surfaces with one or more steps can induce tilting of the fuse link 33 and prevent local stress concentration. The second region 21b in FIG. 16 has multiple (three-step) stepped surfaces 23 lower than the first region 21a. The second region 21b can be flat, curved, or a combination of flat and curved surfaces. The second region 21b can also have unevenness, steps, or slopes, and can combine stepped surfaces 23 and sloped surfaces 22. 17 is an example in which a stepped surface 23 is combined with an inclined surface 22 (flat surface), and the second region 21b in Fig. 18 is an example in which a stepped surface 23 is combined with an inclined surface 22 (curved surface). The height difference, number of steps, combined position with the inclined surface, inclination angle, etc. are determined appropriately depending on the length, tilt position, distance, angle, etc. of the fuse link so as to prevent local stress concentration in the fuse link 33.

[0053] The present invention can be effectively used as a power supply device that can prevent the deterioration of fuse function by avoiding stress concentration on the fuse link without increasing costs.

[0054] DESCRIPTION OF SYMBOLS 100, 200, 900...Power supply device 1...Battery cell 1A...Cylindrical battery 2...Battery holder 3...Lead plate 4...Bus bar 5...External case 6...Battery storage section 7...Partition wall 8...Electrode window 11...Electrode terminal 12...Center electrode 12a...Recessed electrode 13...First end surface 21...End plate 21a...First region 21b...Second region 21c...Third surface 22...Inclined surface 23...Step surface 24...Contact section 25...Non-contact region 28a...Positioning section 28b...Position displacement prevention section 31...Fixed terminal 31a...Welded section 31b...Stepped section 32...Base section 33...Fuse link 33a...First end 33b...Second end 34...Curved section 34a...Arc section 38...Through hole 902...Battery holder 911...electrode terminal 921...end surface plate 921a...first region 931...fixed terminal 933...fuse link 933a...first end

Claims

1. A battery comprising: a plurality of battery cells each having a plurality of electrode terminals arranged thereon; a battery holder that arranges the plurality of battery cells in fixed positions; and a lead plate made of metal and fixed to the plurality of electrode terminals of the plurality of battery cells, wherein each of the plurality of battery cells has a first end face, and a corresponding one of the plurality of electrode terminals is arranged on the first end face of each of the plurality of battery cells, the lead plate having: a base portion; a fixed terminal connected to the corresponding one of the plurality of electrode terminals of the plurality of battery cells; and a fuse link that connects the base portion and the first fixed terminal and has a width narrower than that of the first fixed terminal, wherein the battery holder has an end plate covering the first end faces of each of the plurality of battery cells, the end plate having a plurality of electrode windows that expose at least a portion of each of the plurality of electrode terminals, and the lead plate is connected to the plurality of electrode terminals via the plurality of electrode windows, and the end plate has a first region on the outer periphery and a second region that is arranged inside the first region and close to the electrode terminal side, a base portion of the lead plate facing the first region of the end plate, and a fixed terminal of the lead plate fixed to at least one of the plurality of electrode terminals with the fuse link of the lead plate positioned on the second region of the end plate.

2. A power supply device as claimed in claim 1, wherein said second region has a downwardly inclined surface from the connecting side connected to said first region towards said electrode terminal.

3. A power supply device according to claim 2, wherein said inclined surface has an inclination angle so as to come into surface contact with said fuse link.

4. A power supply device as described in claim 2, wherein the inclination angle of the inclined surface on the base portion side of the second region is smaller than that on the fixed terminal side.

5. A power supply device according to claim 1, wherein the second region has a step surface that is lower than the first region.

6. A power supply device as claimed in claim 1, wherein said second region has a contact portion with which said fuse link comes into contact.

7. A power supply device according to any one of claims 1 to 6, wherein the battery holder has a non-contact area on the second area where the fuse link does not contact the second area.

8. A power supply device according to claim 7, wherein the difference in height between the first region and the second region of the end plate is 0.1 mm or more and 3 mm or less.

9. A power supply device according to claim 7, wherein the height difference between the first region and the second region of the end plate is greater than the maximum height difference tolerance between the first region and the electrode terminal.

10. A power supply device as described in claim 7, wherein the battery cell has an electrode terminal in which a portion of the first end face is recessed.

11. A power supply device as described in claim 7, wherein a plurality of lead plates are arranged on the first end face side of the battery cell.

Images