JP7709290B2 - Battery module and method for manufacturing the battery module - Google Patents

Description

The present invention relates to a battery module in which cylindrical batteries are connected with metal lead plates, and in particular to a battery module in which multiple cylindrical batteries are arranged in parallel with each other so that their first end faces face the same direction, and multiple cylindrical batteries are connected with lead plates on the first end face side, and to a method for manufacturing the battery module.

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. These battery modules are used as power sources for portable electric devices such as electric cleaners and power tools, as backup power sources for servers in stationary power storage applications, and as power sources for home, business, and factory use, as well as the power source for power-assisted bicycles, electric scooters, electric carts, and as the power source for vehicles such as hybrid cars and electric cars.

The cylindrical batteries used in such battery modules are often secondary batteries in which the opening of a cylindrical outer can with a bottom is crimped and closed with a sealing body, with the sealing body serving as the positive electrode and the outer can serving as the negative electrode. In recent years, there has been a demand for improved energy density in battery modules, and as a means of joining cylindrical batteries, progress has been made in moving away from connecting lead plates to the bottom of the can and instead connecting lead plates to crimped ridges provided by crimping on the outer periphery of the sealing body, thereby reducing the required volume and improving volumetric energy density. Conventionally, wire bonding has been used as a means of connecting lead plates to the crimped ridges on the sealing body side of cylindrical batteries.

Wire bonding usually has a wire diameter of about φ500 μm, and since the current capacity is determined by the wire diameter, there are limitations on the current value that can be drawn from one cell, which has led to restrictions on how it can be used (see Patent Document 1). Using a lead plate for connection instead of wire bonding can eliminate the current value limitation, but there is a problem in that it is difficult to accurately and reliably weld the lead plate to the narrow crimp ridge due to tolerance variations in each component.

JP 2010-282811 A

The present invention was developed with the aim of solving the above problems, and one of the objects of the present invention is to provide a battery module and a manufacturing method thereof in which multiple cylindrical batteries are arranged in a parallel position with the positive electrodes facing in the same direction, and the lead plates can be reliably welded to the sealing body and crimping ridges arranged on the same plane.

Means for solving the problem and effects of the invention

A battery module according to one aspect of the present invention includes a plurality of cylindrical batteries having a bottomed cylindrical exterior can with one side open, a battery holder that houses the plurality of cylindrical batteries in a parallel orientation, and lead plates that are connected to the cylindrical batteries and electrically connect the plurality of cylindrical batteries. The opening of the exterior can of the cylindrical battery is crimped and closed with a sealing body, and the end face closed with the sealing body is set as a first end face, and a crimping ridge is provided on the outer periphery of the first end face by crimping. The battery holder holds the plurality of cylindrical batteries so that the first end faces are aligned on the same plane, and is provided with a surface plate portion on the surface facing the first end face, and the surface plate portion has a first electrode window that partially exposes the sealing body of the cylindrical battery and a second electrode window that partially exposes the crimping ridge, and the second electrode window is a curved slit that follows the crimping ridge. The lead plate has a first connection piece that is disposed in the first electrode window and welded to the sealing body, and a second connection piece that is disposed in the second electrode window and welded to the crimp ridge. The second connection piece is a strip that is curved to fit the crimp ridge, and is partially welded to the crimp ridge in at least an area that partially covers the crimp ridge.

The above configuration has the characteristic that, while arranging a plurality of cylindrical batteries, each of which has an opening of an outer can that has been crimped and closed with a sealing body, in a parallel position with the first end faces facing the same direction, the lead plate can be reliably welded to the sealing body and the crimp ridge arranged on the same plane. This is because the above battery module has a first electrode window that exposes the sealing body of the cylindrical battery in the surface plate portion facing the first end face of the cylindrical battery, and a curved, slit-shaped second electrode window that exposes the crimp ridge, and the first connection piece of the lead plate is placed in the first electrode window and welded to the sealing body, and the second connection piece is placed in the second electrode window and welded to the crimp ridge. In particular, the second connection piece of the lead plate has a curved shape that follows the crimp ridge and is partially welded to the crimp ridge at least in the area that covers the crimp ridge, so that the second connection piece can be reliably welded to the crimp ridge to connect the lead plate.

In another aspect of the battery module of the present invention, the crimping ridge is ring-shaped with a predetermined width (D) and has a planar connection area, and the second connection piece is arc-shaped along the connection area and is welded to the connection area.

According to the above configuration, a ring-shaped, planar connection area having a predetermined width (D) is provided on the crimp ridge, and the second connection piece is welded to the connection area in an arc shape that follows the connection area, which has the advantage that the second connection piece can be more accurately welded to the connection area.

In another aspect of the battery module of the present invention, the second connection piece has a welded area where it is partially welded to the crimp ridge, and the welded area has a horizontal width (a) that is equal to or smaller than the horizontal width (D) of the connection area, and a vertical width (b) of the welded area that is equal to or smaller than 1/4 of the overall length (L) of the second connection piece.

According to the above configuration, by setting the welding area of the second connection piece to a specific range, the second connection piece can be more accurately welded to the connection area of the crimped ridge. Here, the total length (L) of the second connection piece refers to the length of the center line passing through the center of the second connection piece in the width direction.

Figure 6A shows a plan view of the first end face of the cylindrical battery 1, and Figure 6B shows a plan view of the second connection piece 32, with the welded area 35 indicated by cross-hatching. In the welding example shown in the figure, the width (a) of the welded area 35 is equal to the width (D) of the connection area, and the length (b) of the welded area is 1/4 or less of the overall length of the second connection piece and 1.5 times the width (D) of the connection area. However, the length (b) of the welded area can also be 0.8 to 3 times the width (D) of the connection area. When ultrasonic welding is performed with the length (b) of the welded area larger than the width (D) of the connection area, the ultrasonic horn for welding can be applied multiple times while shifting its position relative to the welded area.

In another aspect of the battery module of the present invention, the cylindrical batteries are insulated from each other by providing an insulating material between the outer can and the sealing body, and in a plan view of the first end face, the insulating material is exposed on the inside of the crimping ridge to provide a ring-shaped insulating region, and the width (S) of the insulating region is 0.8 to 1.5 times the width (D) of the connection region of the crimping ridge.

According to the above configuration, even if the second connection piece arranged on the crimp ridge is misaligned toward the center of the sealing body, the insulating region provided on the inside of the crimp ridge can effectively prevent the second connection piece from directly contacting the sealing body, and it is possible to avoid a situation in which the crimp ridge and the sealing body are shorted through the second connection piece.

In another aspect of the battery module of the present invention, the width (W) of the second connection piece is 1 to 3 times the width (D) of the connection area of the crimped ridge, the radius of curvature (R1) of the arc-shaped outer edge is greater than the radius of curvature (r1) of the outer edge of the connection area, the radius of curvature (R2) of the arc-shaped inner edge is smaller than the radius of curvature (r2) of the inner edge of the connection area and greater than the radius of curvature (r3) of the inner edge of the insulating area, and the central angle (α) relative to the arc-shaped second connection piece is 135 degrees to 180 degrees.

According to the above configuration, the second connection piece, which is arranged in a stacked state relative to the connection area of the crimped ridge exposed from the second electrode window, is designed to be wide, thereby widening the weldable area, and the welding area can be secured even when the relative position of the second connection piece is misaligned with respect to the cylindrical battery.

In another aspect of the battery module of the present invention, the battery holder positions the inner opening edge of the second electrode window inside the inner edge of the crimp ridge and outside the inner edge of the insulating area, and positions the outer opening edge of the second electrode window outside the outer edge of the crimp ridge, and the opening width (K) of the second electrode window is 1 to 2 times the width (W) of the second connection piece.

According to the above configuration, by defining the positions of the inner and outer peripheral edges of the second electrode window provided in the battery holder, it is possible to position the second connection piece placed in the second electrode window in a position where it can be welded to the crimp ridge, while avoiding the problem of the second connection piece coming into contact with the sealing body.

In another aspect of the battery module of the present invention, the position of the welding area where the second connection piece is welded to the crimp ridge is changed depending on the relative position of the second connection piece to the cylindrical battery when viewed in plan on the first end face of the cylindrical battery.

With the above configuration, even if the position of the second connection piece is misaligned with respect to the crimp ridge due to dimensional errors or the like, the second connection piece can be reliably welded and connected to the crimp ridge.

A manufacturing method of a battery module according to one aspect of the present invention is a manufacturing method of a battery module including a plurality of cylindrical batteries having a bottomed cylindrical outer can with one side open, a battery holder that houses the plurality of cylindrical batteries in a parallel orientation, and lead plates that are connected to the cylindrical batteries and electrically connect the plurality of cylindrical batteries, comprising the steps of: preparing a cylindrical battery in which the opening of the outer can is crimped and closed with a sealing body, the end face closed with the sealing body being the first end face, and a crimping ridge being provided on the outer periphery of the first end face by crimping; preparing a battery holder in which a first electrode window that exposes the sealing body of the cylindrical battery and a second electrode window that exposes the crimping ridge and has a curved slit that follows the crimping ridge are opened in a surface plate portion that is arranged opposite the first end face of the cylindrical battery; and preparing a second electrode window that is arranged in the first electrode window and welded to the sealing body. The method includes the steps of preparing a lead plate having a first connection piece and a second connection piece that is a band-like shape curved along the crimp ridge and is placed in the second electrode window and welded to the crimp ridge; arranging a plurality of cylindrical batteries in fixed positions in a battery holder, holding the plurality of cylindrical batteries so that their first end faces are aligned on the same plane, exposing the sealing body of the cylindrical battery from the first electrode window, and exposing the crimp ridge from the second electrode window; arranging the lead plate in a fixed position in the battery holder, arranging the first connection piece in the first electrode window, and arranging the second connection piece in the second electrode window; and welding the first connection piece placed in the first electrode window to the sealing body and welding the second connection piece placed in the second electrode window to the crimp ridge. In the lead plate welding step, the position of the welding area where the second connection piece is welded to the crimp ridge is changed depending on the relative position of the second connection piece to the cylindrical battery.

The above method allows multiple cylindrical batteries to be arranged in a parallel position with their first end faces facing the same direction, while the lead plates can be reliably welded to the sealing body and crimping ridges arranged on the same plane. In particular, even if the second connection piece is misaligned with respect to the crimping ridge, good welding can be achieved by changing the position of the welding area, allowing for a reliable connection.

In a manufacturing method of a battery module according to one aspect of the present invention, the process of welding the second connection piece to the crimp ridge includes a photographing process, a calculation process, a determination process, and a second connection piece welding process. In the photographing process, a cylindrical battery with a lead plate arranged thereon and the second connection piece are photographed from the first end face side by a camera. In the calculation process, the center position of the cylindrical battery and the center position relative to the arc-shaped second connection piece are calculated from the photographed image. In the determination process, a welding area in which the second connection piece is to be welded to the crimp ridge is specified from the relative position of the center position of the second connection piece to the center position of the cylindrical battery detected in the calculation process. In the second connection piece welding process, the second connection piece is welded to the crimp ridge in the welding area determined in the determination process.

In a manufacturing method of a battery module according to an embodiment of the present invention, in the determining step, the welding area of the second connection piece is specified based on the following conditions.
In a plan view of the first end surface of the cylindrical battery, an XY plane has the center of the cylindrical battery as the origin, and one end of the second connection piece is located in the positive direction on the Y axis, and the other end of the second connection piece is disposed so as to form a central angle (α) extending beyond the positive direction of the X axis into the negative direction of the Y axis.
The center of the cylindrical battery is defined as the first center (O1), and the center of the arc-shaped second connecting piece is defined as the second center (O2), and the welding area at the relative position of the second center (O2) to the first center (O1) is specified to be within the range of an angle (θ) indicated by a radius starting from the positive direction of the X-axis.
(1) When the second center (O2) coincides with the first center (O1), the welding area is any position on the second connecting piece.
(2) When the second center (O2) is located in the negative direction of the X-axis with respect to the first center (O1), the welding area is within the range of 55 degrees≦θ≦90 degrees on the second connecting piece.
(3) When the second center (O2) is located in the positive direction of the X-axis with respect to the first center (O1), the welding area is in the range of 55 degrees≦θ≦85 degrees on the second connecting piece.
(4) When the second center (O2) is located in the positive direction of the Y axis relative to the first center (O1), the welding area is in the range of -35 degrees≦θ≦35 degrees on the second connecting piece.
(5) When the second center (O2) is located in the negative direction of the Y axis with respect to the first center (O1), the welding area is in the range of -35 degrees≦θ≦35 degrees on the second connecting piece.
(6) When the second center (O2) is located in the positive direction of the X-axis and the positive direction of the Y-axis relative to the first center (O1), the welding area is in the range of -65 degrees≦θ≦-20 degrees on the second connecting piece.
(7) When the second center (O2) is located in the negative direction of the X-axis and the positive direction of the Y-axis relative to the first center (O1), the welding area is in the range of 25 degrees≦θ≦70 degrees on the second connecting piece.
(8) When the second center (O2) is located in the negative direction of the X-axis and the negative direction of the Y-axis relative to the first center (O1), the welding area is in the range of -70 degrees≦θ≦-25 degrees on the second connecting piece.
(9) When the second center (O2) is located in the positive direction of the X-axis and the negative direction of the Y-axis relative to the first center (O1), the welding area is in the range of 20 degrees≦θ≦65 degrees on the second connecting piece.

1 is a perspective view of a battery module according to an embodiment of the present invention; 2 is an exploded perspective view of a battery unit of the battery module shown in FIG. 1 . 2 is a plan view of a battery unit of the battery module shown in FIG. 1 . 4 is an enlarged cross-sectional perspective view of the battery unit shown in FIG. 3 taken along line IV-IV. 4 is an enlarged cross-sectional view of the battery unit shown in FIG. 3 taken along line VV. FIG. 6A is an enlarged plan view of a first end of a cylindrical battery. FIG. 6B is an enlarged plan view of the second connecting piece. 10 is a schematic diagram showing a device for welding a second connection piece to a crimping ridge; FIG. FIG. 11 is a plan view showing a concept of identifying a welding position in a determination step. FIG. 11 is a plan view showing a concept of identifying a welding position in a determination step.

The following describes an embodiment of the present invention based on the drawings. However, the following embodiment is an example for embodying the technical idea of the present invention, and the present invention is not limited to the following. In addition, this specification does not specify the members shown in the claims to the members of the embodiment. In particular, the dimensions, materials, shapes, and relative positions of the components described in the embodiment are not intended to limit the scope of the present invention, and are merely explanatory examples, unless otherwise specified. Note that the size and positional relationship of the members shown in each drawing may be exaggerated to clarify the explanation. Furthermore, in the following explanation, the same name and symbol indicate the same or similar members, and detailed explanation will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured as a form in which multiple elements are composed of the same member, and one member serves multiple elements, or conversely, the function of one member can be shared by multiple members.

The battery module of the present invention can be used for a variety of purposes, including as a power source for portable electric devices such as electric cleaners and power tools, as a backup power source for servers in stationary power storage applications, as a power source for storing electricity generated by natural energy sources such as solar power and wind power, as a power source for storing electricity generated overnight, as a power source for households, offices, and factories, and as a power source for driving electric power-assisted bicycles, electric scooters, electric carts, and as a power source for driving vehicles such as hybrid cars and electric cars. Below, we will explain a battery module used as a power source for electric devices as one embodiment of the present invention.

[Embodiment 1]
A battery module 100 according to a first embodiment of the present invention is shown in Figs. 1 to 5. Fig. 1 is a schematic perspective view of a battery module, Figs. 2 and 3 are exploded perspective and plan views of a battery unit of the battery module in Fig. 1, Fig. 4 is an enlarged perspective sectional view of the battery unit shown in Fig. 3 taken along line IV-IV, and Fig. 5 is an enlarged sectional view of the battery unit shown in Fig. 3 taken along line IV-IV. The battery module 100 shown in these figures comprises multiple cylindrical batteries 1, a battery holder 2 that houses the multiple cylindrical batteries 1 in a parallel orientation, and lead plates 3 that are connected to the cylindrical batteries 1 and electrically connect the multiple cylindrical batteries 1. In the battery module 100 shown in Fig. 1, multiple cylindrical batteries 1 are connected via lead plates 3 that are arranged in fixed positions in the battery holder 2 that houses the multiple cylindrical batteries 1 to form a battery unit 10, and this battery unit 10 is housed in an exterior case 9.

(Cylindrical battery 1)
A non-aqueous electrolyte battery such as a lithium ion battery is preferably used as the cylindrical battery 1. Since lithium ion batteries have a large capacity relative to their weight and capacity, the battery module 100 in which the cylindrical battery 1 is a lithium ion battery can be made small and lightweight with a large charge/discharge capacity. However, the present invention does not limit the cylindrical battery to a non-aqueous electrolyte battery, and any battery that can be recharged, such as a nickel-metal hydride battery or a nickel-cadmium battery, can be used.

As shown in FIG. 5, the cylindrical battery 1 is made of a metallic cylindrical outer can 11 with a bottom, which contains a spiral electrode body 13 formed by stacking positive and negative electrode plates 13A and 13B with a separator 13C between them, and is filled with an electrolyte. The opening of the outer can 11 is crimped and closed with a sealing body 12. The sealing body 12 is insulated and hermetically fixed to the outer can 11 via an insulating material 14. The end face of the cylindrical battery 1 that is closed with the sealing body 12 is the first end face 1A, and a crimped ridge 15 is provided on the outer periphery of the first end face 1A by crimping. The cylindrical battery 1, which is a lithium-ion battery, uses the sealing body 12 as the positive electrode and the crimped ridge 15 of the outer can 11 as the negative electrode. The cylindrical battery 1 can be a lithium-ion battery commonly known as "18650" with a diameter of 18 mm and a total length of 65 mm, or a lithium-ion battery close to or larger than these dimensions.

The crimping ridge 15 has a planar connection area 15A to improve the connection with the lead plate 3. The connection area 15A is ring-shaped with a predetermined width (D) and is provided in the inner area excluding the crimped outer edge. By providing the planar connection area 15A with a predetermined width on the surface of the crimping ridge 15, the second connection piece 32 of the lead plate 3, which will be described later, can be welded while being placed in surface contact.

Furthermore, the cylindrical battery 1 in FIG. 5 has a gasket interposed between the upper end opening of the outer can 11 and the sealing body 12 as an insulating material 14, and the sealing body 12 and the outer can 11 are insulated via this gasket. In the cylindrical battery 1 shown in FIG. 5 and FIG. 6A, in a plan view of the first end face 1A, the insulating material 14 arranged between the crimped ridge 15 and the sealing body 12 is extended to the inside of the crimped ridge 15 and exposed to provide a ring-shaped insulating region 16. In this way, by providing the insulating region 16 on the inside of the crimped ridge 15, it is possible to effectively prevent a short circuit caused by contact between the crimped ridge 15 and the sealing body 12. The width (S) of this insulating region 16 can be, for example, 0.8 to 1.5 times the width (D) of the connection region 15A of the crimped ridge 15.

The cylindrical battery 1 shown in FIG. 5 has an insulating region 16 formed by exposing the gasket interposed between the sealing body 12 and the outer can 11, but in a plan view of the first end face 1A of the cylindrical battery 1, a material other than the gasket, such as a resin material, can be placed inside the crimping ridge 15 to insulate the sealing body 12 from the crimping ridge 15, or an insulating paint can be applied to the surface of the sealing body 12 inside the crimping ridge 15 to insulate the sealing body 12 from the crimping ridge 15.

In addition, although not shown, the cylindrical battery can also use a sealing body in which a cap is connected to a sealing plate to form a protruding electrode. In this sealing body, the center part of the cap is connected to the lead plate as the positive electrode.

The cylindrical battery 1 described above is connected to the lead plate 3 using the sealing body 12 and crimped ridges 15 arranged on the first end face 1A as positive and negative electrodes, so the area on the bottom side of the outer can 11, excluding the first end face, can be insulated by covering it with an insulating tube or the like.

(Battery holder 2)
The battery holder 2 is made of thermoplastic resin such as plastic, which is an insulating material. As shown in FIG. 4, the battery holder 2 has surface plates 22, 23 integrally molded and connected to both ends of a holding section 21 through which the cylindrical batteries 1 are inserted and held. In this battery holder 2, the holding section 21 is provided on the inner side of the pair of surface plates 22, 23 that face each other to form a battery storage section. The holding section 21 shown in FIG. 2 and FIG. 4 is tubular and conforms to the outer periphery of the cylindrical batteries 1, or tubular with partial openings. The pair of surface plates 22, 23 are located at both ends of the holding section 21 and are arranged in parallel to each other. The surface plates 22, 23 are molded into a plate shape that is perpendicular to the holding section 21. As shown in FIG. 1 and FIG. 2, the battery holder 2 holds the multiple cylindrical batteries 1 inserted into each holding section 21 in fixed positions by arranging them in multiple rows and columns.

2 and 4, the battery holder 2 has a holding section 21 divided into two in the axial direction, and the ends of the divided holding section 21 are molded integrally with the surface plate sections 22 and 23 to form a pair of holder units 2A and 2B. This battery holder 2 holds multiple cylindrical batteries 1 so that their first end faces 1A are aligned on the same plane. Therefore, the holder unit 2A, in which the first end faces 1A of the cylindrical batteries 1 are arranged, has an electrode window in the surface plate section 22 that exposes the sealing body 12 and crimping ridge 15, which are the positive and negative electrodes arranged on the first end faces 1A. In contrast, the holder unit 2B, in which the can bottom of the cylindrical batteries 1 are arranged, does not have an opening in the surface plate section 23, and one end of the holding section 21 is closed by the surface plate section 23. With cylindrical batteries 1 stored in the holding sections 21 of each holder unit 2A and 2B, the pair of holder units 2A and 2B are connected to form a battery storage section that holds the cylindrical batteries 1 in a fixed position. The pair of holder units 2A, 2B are connected and fixed to each other. The divided holder units can be connected via connectors such as ultrasonic welding, adhesives, locking structures, and locking screws. In the above-described battery holder 2, half of the holding portion 21 and the surface plate portions 22, 23 are integrally molded to form the holder units 2A, 2B, but the battery module 100 does not limit the battery holder to the above structure. The battery holder can have any other structure capable of holding multiple batteries in a predetermined position.

The holder unit 2A has a first electrode window 25 that exposes the sealing body 12 of the cylindrical battery 1 and a second electrode window 26 that exposes the crimping protrusion 15 on the surface plate portion 22 that is arranged on the surface opposite the first end face 1A. The first electrode window 25 is a circular through hole that is opened at a position opposite the center of the sealing body 12. The first electrode window 25 is large enough to expose the center part of the sealing body 12, and the first connection piece 31 of the lead plate 3 described later is welded to this part. Furthermore, by opening the first electrode window 25 widely, it is possible to quickly exhaust gas discharged from the sealing body 12 of the cylindrical battery 1 to the outside of the cylindrical battery 1. However, the first electrode window 25 does not necessarily have to open in a large circular shape, and can be polygonal or opened in a size that allows only the first connection piece to be placed.

The second electrode window 26 is a slit-shaped curved shape that follows the crimping ridge 15 formed on the first end face 1A. As shown in FIG. 3, the slit-shaped second electrode window 26 is formed in a curved shape that follows approximately half of the outer periphery of the cylindrical battery 1 in a plan view. As shown in FIG. 5, the inner opening edge 26a of the second electrode window 26 is located inside the inner periphery of the crimping ridge 15 and outside the inner periphery of the insulating region 16, and the outer opening edge 26b of the second electrode window 26 is located outside the outer periphery of the crimping ridge 15. Furthermore, the second electrode window 26 shown in the figure is a slit-shaped shape that follows the outer shape of the second connection piece 32 that extends in a strip shape, and the second connection piece 32 can be positioned by inserting the second connection piece 32 along the inner surface of the second electrode window 26. The opening width (K) of the second electrode window 26 can be 1 to 2 times the width (W) of the second connection piece 32 that is guided therethrough.

Furthermore, the surface plate portion 22 shown in FIG. 4 is provided with a boss 24 for positioning the lead plate 3 in a fixed position. The boss 24 is formed in a position that protrudes from the surface of the surface plate portion 23. The lead plate 3 has a positioning hole 34 that is guided by the boss 24, and the boss 24 is guided into this positioning hole 34 to position the lead plate 3 in a fixed position on the surface plate portion 23.

(Lead plate 3)
The lead-plates 3 are placed in fixed positions on the surface plate 22 and are connected to the positive and negative electrodes of the multiple cylindrical batteries 1, connecting the multiple cylindrical batteries 1 in a predetermined arrangement. The lead-plate 3 is a thin metal plate that is connected to the seal 12 and crimping ridge 15 located on the first end face 1A of each cylindrical battery 1. The lead-plate 3 shown in the figure has a first connection piece 31 that is placed in the first electrode window 25 and welded to the seal 12, and a second connection piece 32 that is placed in the second electrode window 26 and welded to the crimping ridge 15. The lead-plate 3 shown in the figure has a main body 30 that is placed on the surface of the surface plate 22, with multiple first connection pieces 31 that protrude from one side of the main body 30 and are integral with it, and multiple second connection pieces 32 that protrude from the opposite side of the main body 30 and are integral with it. The main body 30 shown in the figure extends in the direction in which the rows of cylindrical batteries 1 extend, and is arched to fit the edge of the second electrode window 26. The lead plate 3 is made from an elastically deformable metal plate made of aluminum, nickel, copper, or an alloy of these.
The lead plate 3 may be, for example, a polycarbonate sheet having a thickness of about 0.2 mm, to which the main body 30, the first connecting piece 31 and the second connecting piece 32 are attached in advance to be integrated. The sheet is preferably made of aramid paper or the like.

The first connection piece 31 has a connection portion at the tip of an arm portion extending from the main body 30, and this connection portion is welded and connected to the center of the sealing body 12. The first connection piece 31 connected to the sealing body 12 is connected, for example, by spot welding. The lead plate 3 is connected to the sealing body 12 via the first connection piece 31 connected to the main body 30, as shown in FIG. 4.

As shown in Figs. 3 and 4, the second connection piece 32 is a belt-like shape curved to fit along the crimp ridge 15. The second connection piece 32 shown in Fig. 6B is an arc-shaped piece that fits along the connection area 15A of the crimp ridge 15 shown in Fig. 6A. The second connection piece 32 formed in an arc shape is formed so that the radius of curvature (R1) of the outer edge of the arc shape is larger than the radius of curvature (r1) of the outer edge of the connection area 15A, the radius of curvature (R2) of the inner edge of the arc shape is smaller than the radius of curvature (r2) of the inner edge of the connection area 15A, and is larger than the radius of curvature (r3) of the inner edge of the insulating area 16. This allows the width (W) of the second connection piece 32 to be wider than the connection area 15A of the crimp ridge 15. The width (W) of the second connection piece 32 can be 1 to 3 times the width (D) of the connection area 15A of the crimp ridge 15. Furthermore, the second connection piece 32 shown in FIG. 6B has a central angle (α) relative to the arc-shaped second connection piece 32 of 135 degrees to 180 degrees, and preferably 145 degrees to 170 degrees. By setting the central angle (α) of the second connection piece 32 in the above range, it is possible to ensure the welding area 35 even if the position is misaligned in any direction.

The second connection piece 32 is partially welded to the crimp ridge 15 at least in the area covering the crimp ridge 15. The second connection piece 32 can be provided with a welding area 35 so as to be partially welded to the crimp ridge 15, and as shown in FIG. 6, the width (a) of the welding area 35 is equal to or smaller than the width (D) of the connection area 15A, and the vertical width (b) of the welding area 35 is equal to or smaller than 1/4 of the total length (L) of the second connection piece 32. Here, the total length (L) of the second connection piece 32 indicates the length of the center line passing through the center of the width direction of the second connection piece 32, as shown in FIG. 6B. In this way, by setting the welding area 35 of the second connection piece to a specific range, the second connection piece 32 can be more accurately welded to the connection area 15A of the crimp ridge 15.

The second connection piece 32 is connected to the crimp ridge 15 by ultrasonic welding. In ultrasonic welding, an ultrasonic horn is pressed against the surface of the second connection piece 32, and the second connection piece 32 is ultrasonically vibrated while being pressed against the crimp ridge 15, thereby connecting the second connection piece 32 to the crimp ridge 15. In ultrasonic welding, the second connection piece 32 is ultrasonically vibrated in a direction parallel to the surface of the crimp ridge 15, connecting the second connection piece 32 to the crimp ridge 15. In ultrasonic welding, the metals are molecularly bonded at the interface to connect the second connection piece 32 to the crimp ridge 15, so that dissimilar metals can be stably connected. Therefore, the aluminum lead plate 3 can be reliably and stably fixed to the crimp ridge 15 of the iron outer can 11. The second connection piece 32, which is long and easily deformed, is characterized by being able to flexibly deform during the process of ultrasonically welding the welding area 35 to the crimping ridge 15, allowing for a reliable connection with less ultrasonic vibration energy.

The battery unit 10 in Figure 3 has multiple lead plates 3 arranged on the first end face 1A side of the cylindrical batteries 1, and multiple cylindrical batteries 1 arranged in multiple rows and columns are connected in multiple parallel and multiple series. The battery unit 10 shown in the figure has multiple cylindrical batteries 1 arranged in a parallel position with their first end faces positioned on the same plane, and connected in series and parallel on the first end face 1A side. The battery unit 10 shown in the figure has 12 cylindrical batteries 1 arranged in four rows and three columns, connected in four parallel and three series.

Each lead plate 3 has four first connection pieces 31 and four second connection pieces 32. The four first connection pieces 31 are connected to the sealing bodies 12 of four adjacent cylindrical batteries 1, connecting these four cylindrical batteries 1 in parallel, and the four second connection pieces 32 are connected to the crimp ridges 15 of the four cylindrical batteries 1 adjacent to the four cylindrical batteries 1 connected in parallel, connecting these four cylindrical batteries 1 in parallel and connecting the four cylindrical batteries 1 connected in parallel in series. In other words, the lead plate 3 connects the multiple cylindrical batteries 1 arranged in each tier in parallel, and also connects the multiple cylindrical batteries 1 arranged in adjacent tiers in series. In this way, the four cylindrical batteries 1 arranged in one tier are connected in parallel, while the two tiers of adjacent cylindrical batteries 1 are connected in series.

Furthermore, of the cylindrical batteries 1 arranged in series in multiple tiers, output lead plate 3A is connected to the cylindrical battery 1 located in the frontmost tier in the figure, and output lead plate 3B is connected to the cylindrical battery 1 located in the rearmost tier. One output lead plate 3A has four first connection pieces 31 connected to the sealing plate 12, and the first connection pieces 31 are respectively connected to the four cylindrical batteries 1 located at the front of the multiple tiers of cylindrical batteries 1 connected in series with each other, connecting these four cylindrical batteries 1 in parallel with each other. The output lead plate 3A in Figure 1 has a bent terminal section 3a bent at a right angle at the end opposite the first connection pieces 31, and this bent terminal section 3a is located on the side of the battery holder 2. The other output lead-plate 3B has four second connection pieces 32 that connect to the crimp ridges 15, and the second connection pieces 32 are connected to the four rearmost cylindrical batteries 1 of the multiple rows of cylindrical batteries 1 that are connected in series with each other, connecting these four cylindrical batteries 1 in parallel. The end of the output lead-plate 3B opposite the second connection pieces 32 is bent at a right angle to provide a bent terminal portion 3b, which is located on the side of the battery holder 2.

Although not shown, the battery module can also be constructed by arranging multiple battery units 10 vertically (top-bottom in FIG. 3) and connecting the bent terminals 3a, 3b of the output lead plates 3A, 3B arranged on the side of the battery holder 2 directly or with a bus bar or the like to connect multiple battery units 10 in series to increase the output voltage, or by arranging multiple battery units 9 horizontally (left-right in FIG. 3) and connecting the bent terminals 3a, 3b of the output lead plates 3A, 3B arranged on the side of the battery holder 2 with a bus bar or the like to connect multiple battery units 10 in parallel.

Here, the cylindrical battery 1 is placed in a fixed position when inserted into the holding portion 21 of the battery holder 2, but the position of the cylindrical battery 1 may shift from the fixed position of the battery holder 2 due to dimensional differences between the battery and the battery holder 2. The exact position of the second connection piece 32 placed in the second electrode window 26, which is a curved slit, may also shift. In particular, since the second connection piece 32 is made of a curved metal plate, it may shift in position relative to the cylindrical battery 1 even when placed in the curved window of the battery holder. In order to ensure that the second connection piece 32, which is placed out of position, is welded to the crimping ridge 15 of the cylindrical battery 1 in this way, the battery module 100 shown in the figure is designed to ensure that the second connection piece 32 is welded to the crimping ridge 15 by shifting the welding area 35 when the second connection piece 32 shifts in position relative to the cylindrical battery 1.

The above battery module is manufactured in the following steps.
(1) Cylindrical battery preparation process In this process, a cylindrical battery is prepared by crimping the opening of a bottomed cylindrical outer can and closing it with a sealing body, and providing a crimped ridge on the outer periphery of the first end face closed by the sealing body by crimping.
(2) Battery holder preparation process In this process, a battery holder is prepared in a surface plate portion positioned opposite the first end face of the cylindrical battery, the surface plate portion having a first electrode window partially exposing the sealing body of the cylindrical battery, and a second electrode window partially exposing the crimping ridge, the second electrode window having a curved slit that follows the crimping ridge.
(3) Lead Plate Preparation Step In this step, a lead plate 3 is prepared, which includes a first connection piece 31 that is placed in the first electrode window 25 and welded to the sealing body 12, and a band-like second connection piece 32 that is curved to fit the crimping ridge 15, is placed in the second electrode window 26 and welded to the crimping ridge 15. The lead plate 3 is prepared with a plurality of first connection pieces and second connection pieces arranged in a predetermined array to match the connection state of the cylindrical batteries 1 to be connected.
(4) Cylindrical battery arrangement process: A number of cylindrical batteries are arranged in fixed positions in the battery holder, and the multiple cylindrical batteries are held so that their first end faces are aligned in the same plane. The sealing bodies 12 of the cylindrical batteries 1 are exposed from the first electrode windows 25, and the crimping ridges 15 are exposed from the second electrode windows 26.
(5) Lead Plate Arrangement Step The lead plate 3 is arranged in a fixed position in the battery holder 2 , the first connection piece 31 is arranged in the first electrode window 25 , and the second connection piece 32 is arranged in the second electrode window 26 .
(6) Lead plate welding process The first connection piece 31 arranged in the first electrode window 25 is welded to the sealing body 12, and the second connection piece 32 arranged in the second electrode window 26 is welded to the crimping ridge 15. Furthermore, in this process, the position of the welding area where the second connection piece 32 is welded to the crimping ridge 15 is changed depending on the relative position of the second connection piece 32 to the cylindrical battery 1.

Furthermore, in the lead plate welding process for welding the second connection piece 32 to the crimping ridge 15, the second connection piece 32 is precisely welded to the connection area 15A of the crimping ridge 15 in the process described below.
(a) a photographing process;
As shown in Figure 7, the cylindrical battery 1 with the lead plate 3 in place and the second connection piece 32 are photographed from the first end face 1A side by a camera 41. The camera 41 is positioned away from the center axis of the cylindrical battery 1 so that it can photograph the cylindrical battery 1 seal 12 and the second connection piece 32 set in a fixed position. The camera 41 detects images of the cylindrical battery 1 seal 12 and second connection piece 32. Cameras used in various sensors, such as a CCD camera, can be used as this type of camera 41. Data on the ring-shaped image captured by the camera 41 is input to the calculation circuit of the control circuit.
(b) Calculation step The image captured by the camera 41 is processed by a calculation circuit to detect the centre position of the cylindrical battery 1 and its centre position relative to the arc-shaped second connecting piece 32 .
(c) Determination process In this process, the determination circuit 43 identifies the welding area for welding the second connection piece 32 to the crimping ridge 15 based on the relative position of the center position of the second connection piece 32 to the center position of the cylindrical battery 1 detected by the calculation circuit 42.

The judgment circuit stores the optimal welding position for the relative positions of the cylindrical battery 1 and the second connection piece 32 as a table or function, and determines the optimal welding position based on this, and welds the second connection piece 32 to the crimping ridge 15 at the determined welding position.
The determination circuit identifies the welding area based on the conditions shown in FIGS.

8 and 9 show the results of verification in a plan view of the first end surface 1A of the cylindrical battery 1 in an XY plane with the center of the cylindrical battery 1 as the origin, with one end of the second connection piece 32 positioned in the positive direction on the Y axis and the other end of the second connection piece 32 positioned at a central angle (α) that extends beyond the positive direction of the X axis into the negative direction of the Y axis. With the center of the cylindrical battery being the first center (O1) and the center of the arc-shaped second connection piece 32 being the second center (O2), the welding area 35 at the relative position of the second center (O2) to the first center (O1) is specified to be within the range of the following angle (θ) indicated by a radius starting from the positive direction of the X axis.
(1) When the second center (O2) coincides with the first center (O1), the welding area 35 is at any position on the second connection piece 32.
(2) When the second center (O2) is located in the negative direction of the X-axis with respect to the first center (O1), the welding area 35 is within the range of 55 degrees≦θ≦90 degrees on the second connecting piece 32.
(3) When the second center (O2) is located in the positive direction of the X-axis relative to the first center (O1), the welding area 35 is in the range of 55 degrees≦θ≦85 degrees on the second connecting piece 32.
(4) When the second center (O2) is located in the positive direction of the Y axis relative to the first center (O1), the welding area 35 is in the range of −35 degrees≦θ≦35 degrees on the second connecting piece 32.
(5) When the second center (O2) is located in the negative direction of the Y axis with respect to the first center (O1), the welding area 35 is in the range of −35 degrees≦θ≦35 degrees on the second connecting piece 32.
(6) When the second center (O2) is located in the positive direction of the X-axis and the positive direction of the Y-axis relative to the first center (O1), the welding area 35 is in the range of -65 degrees≦θ≦-20 degrees on the second connecting piece 32.
(7) When the second center (O2) is located in the negative direction of the X-axis and the positive direction of the Y-axis relative to the first center (O1), the welding area 35 is in the range of 25 degrees≦θ≦70 degrees on the second connection piece 32.
(8) When the second center (O2) is located in the negative direction of the X-axis and the negative direction of the Y-axis relative to the first center (O1), the welding area 35 is in the range of -70 degrees≦θ≦-25 degrees on the second connection piece 32.
(9) When the second center (O2) is located in the positive direction of the X-axis and the negative direction of the Y-axis relative to the first center (O1), the welding area 35 is in the range of 20 degrees≦θ≦65 degrees on the second connection piece 32.

(d) Second Connection Piece Welding Step In this step, the second connection piece 32 is welded to the crimping ridge 15 in the welding area 35 determined in the determination step. Fig. 7 shows a state in which the control unit 44 drives the ultrasonic welder based on the determination of the determination circuit 43. The control unit 44 controls the moving mechanism 46 to move the ultrasonic horn 45 to the welding position. With the tip of the ultrasonic horn 45 positioned at the welding position, the control unit 44 outputs a drive signal to the output unit 47 to perform ultrasonic welding.
Through the above steps, the second connection piece 32 is welded to the crimp ridge 15 at an optimal position and securely connected.

The present invention is a battery module consisting of multiple cylindrical batteries connected by metal lead plates, and is particularly suitable for use as a battery module in which the cylindrical batteries are arranged in parallel with each other so that their first end faces face the same direction, and multiple cylindrical batteries are connected by lead plates on the first end face side.

DESCRIPTION OF SYMBOLS 100...battery module 1...cylindrical battery 1A...first end surface 2...battery holder 2A, 2B...holder unit 3...lead plates 3A, 3B...output lead plates 3a, 3b...bent terminal portion 9...outer case 10...battery unit 11...outer can 12...sealing body 13...electrode body 13A...electrode plate 13B...electrode plate 13C...separator 14...insulating material 15...crimping ridge 15A...connection region 16...insulating region 21...holding portion 22...surface plate portion 23...surface plate portion 24...boss 25...first electrode window 26...second electrode window 26a, 26b...opening edge 30...main body portion 31...first connection piece 32...second connection piece 34...positioning hole 35...welding region 41...camera 42...arithmetic circuit 43...determination circuit 44...control unit 45...ultrasonic horn 46...movement mechanism 47...output section

Claims (9)

A plurality of cylindrical batteries each having a cylindrical exterior can with a bottom that is open on one side;
a battery holder that houses a plurality of the cylindrical batteries in a parallel orientation;
a lead plate connected to the cylindrical battery to electrically connect a plurality of the cylindrical batteries;
A battery module comprising:
the cylindrical battery has an opening of the exterior can that is crimped and closed with a sealing body, the end face that is closed with the sealing body being a first end face, and a crimped ridge is provided on an outer periphery of the first end face by crimping,
the battery holder holds the cylindrical batteries so that the first end faces are aligned on the same plane, and includes a surface plate portion on a surface opposite the first end face;
The surface plate portion includes:
a first electrode window that partially exposes the sealing body of the cylindrical battery;
A second electrode window is formed to partially expose the crimping ridge,
The second electrode window is a curved slit that is aligned with the crimping protrusion,
The lead plate is
a first connection piece disposed in the first electrode window and welded to the sealing body;
a second connection piece that is disposed in the second electrode window and welded to the crimping protrusion,
the second connection piece is a belt-like shape curved along the crimping ridge and is partially welded to the crimping ridge at least in a region covering the crimping ridge,
A battery module in which the position of a welding area for welding the second connection piece to the crimping protrusion is changed depending on the relative position of the second connection piece with respect to the cylindrical battery when viewed in a plan view of the first end face of the cylindrical battery . The battery module according to claim 1 ,
The crimping protrusion has a ring shape having a predetermined width (D) and a planar connection area,
The second connection piece has an arc shape that follows the connection area, and is welded to the connection area of the battery module. The battery module according to claim 2,
The second connection piece has a welding area that is partially welded to the crimping protrusion, and the welding area has a horizontal width (a) that is less than or equal to the horizontal width (D) of the connection area, and a vertical width (b) of the welding area that is less than or equal to 1/4 of the overall length (L) of the second connection piece. The battery module according to claim 2 or 3,
the cylindrical battery has an insulating material disposed between the exterior can and the sealing body to insulate them from each other, and the insulating material is exposed on the inside of the crimping protrusion in a plan view of the first end face to provide a ring-shaped insulating region;
The battery module has a width (S) of the insulating region that is 0.8 to 1.5 times the width (D) of the connection region of the crimping ridge. The battery module according to claim 4,
the second connection piece has a width (W) that is 1 to 3 times the width (D) of the connection region of the crimping ridge, a radius of curvature (R1) of the arc-shaped outer edge is larger than the radius of curvature (r1) of the outer peripheral edge of the connection region, a radius of curvature (R2) of the arc-shaped inner edge is smaller than the radius of curvature (r2) of the inner peripheral edge of the connection region and larger than the radius of curvature (r3) of the inner peripheral edge of the insulating region, and a central angle (α) relative to the arc-shaped second connection piece is 135 degrees to 180 degrees. The battery module according to claim 4 or 5,
The battery holder is a battery module in which the inner opening edge of the second electrode window is positioned inside the inner edge of the crimping ridge and outside the inner edge of the insulating area, and the outer opening edge of the second electrode window is positioned outside the outer edge of the crimping ridge, and the opening width (K) of the second electrode window is 1 to 2 times the width (W) of the second connecting piece. A plurality of cylindrical batteries;
a battery holder that houses a plurality of the cylindrical batteries in a parallel orientation;
a lead plate connected to the cylindrical battery to electrically connect a plurality of the cylindrical batteries;
A manufacturing method of a battery module comprising:
preparing the cylindrical battery by crimping an opening of a bottomed cylindrical exterior can with a sealing body, defining the end face closed by the sealing body as a first end face, and providing a crimped ridge on an outer periphery of the first end face by crimping;
preparing a battery holder having a surface plate portion disposed opposite the first end face of the cylindrical battery, the surface plate portion having a first electrode window exposing the sealing body of the cylindrical battery and a second electrode window exposing the crimping ridge, the second electrode window having a curved slit that conforms to the crimping ridge;
preparing a lead plate including a first connection piece disposed in the first electrode window and welded to the sealing body, and a second connection piece having a belt shape curved along the crimping ridge, the second connection piece disposed in the second electrode window and welded to the crimping ridge;
placing a plurality of the cylindrical batteries in fixed positions in the battery holder to hold the plurality of cylindrical batteries so that the first end faces are aligned on the same plane, exposing the sealing bodies of the cylindrical batteries through the first electrode window, and exposing the crimping ridges through the second electrode window;
placing the lead plate in a fixed position in the battery holder, with the first connection piece being placed in the first electrode window and the second connection piece being placed in the second electrode window;
welding the first connection piece disposed in the first electrode window to the sealing body, and welding the second connection piece disposed in the second electrode window to the crimping protrusion,
a welding area for welding the second connection piece to the crimping ridge, the welding area being changed depending on the relative position of the second connection piece to the cylindrical battery, in the lead plate welding step. A method for manufacturing a battery module according to claim 7 , comprising the steps of:
The step of welding the second connection piece to the crimping protrusion includes:
an imaging step of imaging the cylindrical battery with the lead plate disposed thereon and the second connection piece from the first end surface side with a camera;
a calculation step of calculating a center position of the cylindrical battery and a center position relative to the arc-shaped second connection piece from the captured image;
a determination step of determining a welding area for welding the second connection piece to the crimping protrusion based on a relative position of a center position of the second connection piece with respect to the center position of the cylindrical battery detected in the calculation step;
a second connection piece welding step of welding the second connection piece to the crimping ridge in the welding area determined in the determination step. A method for manufacturing a battery module according to claim 8 , comprising the steps of:
The method for manufacturing a battery module, in which the determination step identifies the welding area of the second connection piece based on the following conditions:
In a plan view of the first end surface of the cylindrical battery, an XY plane has the center of the cylindrical battery as the origin, and one end of the second connection piece is located in the positive direction on the Y axis, and the other end of the second connection piece is disposed at a central angle (α) extending beyond the positive direction of the X axis into the negative direction of the Y axis.
The center of the cylindrical battery is defined as a first center (O1), and the center of the arc-shaped second connection piece is defined as a second center (O2), and the welding area at the relative position of the second center (O2) to the first center (O1) is specified to be within the range of an angle (θ) indicated by a radius starting from the positive direction of the X-axis.
(1) When the second center (O2) coincides with the first center (O1), the welding area is any position on the second connecting piece.
(2) When the second center (O2) is located in the negative direction of the X-axis with respect to the first center (O1), the welding area is within the range of 55 degrees≦θ≦90 degrees on the second connecting piece.
(3) When the second center (O2) is located in the positive direction of the X-axis relative to the first center (O1), the welding area is in the range of 55 degrees≦θ≦85 degrees on the second connecting piece.
(4) When the second center (O2) is located in the positive direction of the Y axis relative to the first center (O1), the welding area is in the range of -35 degrees≦θ≦35 degrees on the second connecting piece.
(5) When the second center (O2) is located in the negative direction of the Y axis relative to the first center (O1), the welding area is in the range of -35 degrees≦θ≦35 degrees on the second connecting piece.
(6) When the second center (O2) is located in the positive direction of the X-axis and the positive direction of the Y-axis relative to the first center (O1), the welding area is in the range of -65 degrees≦θ≦-20 degrees on the second connecting piece.
(7) When the second center (O2) is located in the negative direction of the X-axis and the positive direction of the Y-axis relative to the first center (O1), the welding area is in the range of 25 degrees≦θ≦70 degrees on the second connecting piece.
(8) When the second center (O2) is located in the negative direction of the X-axis and the negative direction of the Y-axis relative to the first center (O1), the welding area is in the range of -70 degrees≦θ≦-25 degrees on the second connecting piece.
(9) When the second center (O2) is located in the positive direction of the X-axis and the negative direction of the Y-axis relative to the first center (O1), the welding area is in the range of 20 degrees≦θ≦65 degrees on the second connecting piece.