JP7788882B2 - Battery Module - Google Patents

Description

The present invention relates to a battery module in which multiple battery cells are connected in series or parallel with lead plates.

A battery module has been developed in which multiple battery cells are positioned in fixed positions using cell holders, and lead plates are welded to the positive and negative electrodes of each battery cell (see Patent Document 1). In this battery module, both the battery cells and lead plates are positioned in fixed positions using the cell holder, and the connection leads of the lead plates are welded to the battery cell electrodes. In this battery module, the lead plates are positioned in fixed positions in the cell holder using an interlocking structure, and the connection leads are positioned opposite the positive and negative electrodes of the battery cells. The connection leads positioned opposite the battery cell electrodes can be welded by contacting them with the electrode surfaces in a pressed state.

International Publication No. 2021/111842 Special table 2016-516273 publication

In a structure in which both the battery cell and the lead plates are fitted into the cell holder to position the battery cell electrodes and the connection leads are welded to the battery cell electrodes, the battery cell electrodes and the welded connection leads must be positioned precisely opposite each other during the welding process. In particular, battery modules have been developed in which lead plates are positioned on only one end face of the battery cell. However, because these battery modules connect positive and negative connection leads to one end face of the battery cell, the lead plates and battery electrodes must be positioned relative to each other with extremely high precision (see Patent Document 2). However, in a structure in which the battery cell and the lead plates are fitted into the cell holder to position the battery cells in fixed positions, it is extremely difficult to position them relative to each other with high precision during the actual manufacturing process. This is because errors in the cell holder molding process, errors in the battery cell manufacturing process, and errors in the lead plate cutting process can cause misalignment between the welded portions and the electrodes. Increasing the dimensional precision of the cell holder, battery cell, and lead plate can reduce the relative positional misalignment between the welded portion and the electrode, but increasing the dimensional precision of each component has drawbacks such as increased manufacturing costs due to the need for higher processing precision and reduced yield. Furthermore, in a battery module, reliably and stably welding the lead plate and electrodes is an extremely important characteristic, as it ensures the reliability and stability of the battery module itself.

The present invention was developed with the aim of further resolving the above-mentioned problems, and one object of the present invention is to provide a battery module that can be mass-produced efficiently while ensuring a reliable and stable connection between the battery cells and lead plates.

A battery module according to one embodiment of the present invention comprises multiple battery cells, lead plates formed by welding connection leads to the electrodes of the battery cells, and a cell holder connecting the battery cells and the lead plates. The cell holder has a positioning stopper that positions the lead plate in a fixed position, and the lead plate has an elastic arm portion that elastically presses against the cell holder and a collision portion that is urged by the reaction of the elastic arm portion pressing against the cell holder and abuts against the positioning stopper. Furthermore, the lead plate is positioned on the cell holder so that it can be displaced in a direction that brings the collision portion closer to the positioning stopper. In the battery module, the lead plate is displaced by the reaction of the elastic arm portion pressing against the cell holder, and the collision portion of the lead plate abuts against the positioning stopper, positioning the lead plate in a fixed position in the cell holder.

The purpose of the above battery module is to provide a battery module that can be mass-produced efficiently while ensuring a reliable and stable connection between the battery cells and lead plates.

1 is a schematic exploded perspective view of a battery module according to an embodiment of the present invention; FIG. 2 is an exploded perspective view showing the connection structure between the cell holder, the lead plate, and the battery cell. FIG. 2 is a plan view showing a positioning structure for a cell holder and a lead plate. FIG. 2 is a perspective view showing a positioning structure for a cell holder and a lead plate. FIG. 2 is a cross-sectional perspective view showing a positioning structure for a cell holder and a lead plate. FIG. 2 is a plan view showing the connection state between the lead plates and the battery cells. FIG. 4 is an enlarged plan view showing a connection state between a first connection lead and a peripheral electrode. FIG. 10 is a plan view showing a positioning structure for a cell holder and a lead plate according to a modified example. 10 is a partially enlarged plan view showing a lead-plate positioning structure for a battery module according to another embodiment of the present invention. FIG. 10 is a partially enlarged plan view showing a lead-plate positioning structure for a battery module according to another embodiment of the present invention. FIG. 10 is a partially enlarged plan view showing a lead-plate positioning structure for a battery module according to another embodiment of the present invention. FIG. 10 is a partially enlarged plan view showing a lead-plate positioning structure for a battery module according to another embodiment of the present invention. FIG. FIG. 10 is a schematic exploded perspective view of a battery module according to a modified example.

A battery module according to one embodiment of the present invention includes a plurality of battery cells, lead plates formed by welding connection leads to the electrodes of the battery cells, and a cell holder formed by connecting the battery cells and the lead plates. The cell holder includes a positioning stopper that positions the lead plate in a fixed position. The lead plate includes an elastic arm portion that elastically presses the cell holder and a collision portion that is urged by the reaction of the elastic arm portion pressing the cell holder and abuts against the positioning stopper. The lead plate is disposed on the cell holder so as to be displaceable in a direction that brings the collision portion closer to the positioning stopper. In the battery module, the lead plate is displaced by the reaction of the elastic arm portion pressing the cell holder, and the collision portion of the lead plate abuts against the positioning stopper, thereby positioning the lead plate in a fixed position on the cell holder. The cell holder and the lead plate are connected via a connecting mechanism that can displace their relative positions in a direction that brings the collision portion closer to the positioning stopper. The connecting mechanism comprises a connecting hole provided in the lead plate and an insertion boss provided in the cell holder and inserted into the connecting hole, and a displacement gap is provided between the connecting hole and the insertion boss in a direction that allows the collision part to approach the position regulating stopper.

The above battery module allows the connection leads of the lead plates to be welded to the battery cell electrodes while the lead plates are connected in a fixed position on the cell holder. In particular, it has the advantage of absorbing errors in the manufacturing processes for the battery cells, cell holders, and lead plates, positioning the lead plates and battery cells in fixed positions, and reliably welding the connection leads to the battery cell electrodes. This is because the above battery module presses the cell holder with the elastic arm portion on the lead plate, bringing the impact portion of the lead plate into contact with the cell holder's position-regulating stopper, eliminating any relative positional misalignment between the lead plate and cell holder when connecting them.

Reliable and stable welding of the lead plate's connection leads to the battery cell electrodes is extremely important in battery modules. Reliable welding of the lead plate to the battery cell can be achieved by accurately positioning the lead plate's connection leads and the battery cell electrodes in opposing positions. Lead plates are welded to the battery cell electrodes using methods such as laser welding, spot welding, and ultrasonic welding, but misalignment between the connection leads and the electrodes relative to each other can hinder reliable welding and cause problems such as the connection leads coming into contact with electrodes to which they are not connected. Relative misalignment between the two can be achieved by increasing the machining precision of the battery cells, cell holders, and lead plates, but improving the machining precision of these components is extremely difficult in actual manufacturing processes and further increases manufacturing costs. Therefore, mass-produced battery modules require a structure that reliably welds the lead plates to the electrodes while minimizing manufacturing costs.

In another embodiment of the battery module of the present invention, the cell holder and the lead plate can be connected via a connecting mechanism that can displace the relative positions of the two in a direction that brings the collision portion closer to the position-regulating stopper.

The above battery module uses a connecting mechanism to connect the lead plates and cell holders in a displaceable manner, and the lead plates are positioned in a fixed position on the cell holder by the reaction force of the elastic arm pressing against the cell holder. This allows for efficient mass production while reducing assembly costs by connecting the lead plates and cell holders.

In another embodiment of the battery module of the present invention, the connection mechanism includes a connection hole provided in the lead plate and an insertion boss provided in the cell holder and inserted into the connection hole, and a displacement gap can be provided between the connection hole and the insertion boss in a direction that brings the collision portion closer to the position-regulating stopper. The above battery module has a simple structure in which the insertion boss of the cell holder is inserted into the connection hole of the lead plate, and has the advantage of being able to connect the lead plate and cell holder in a predetermined direction with freedom of movement.

In a battery module according to another embodiment of the present invention, the positioning stopper can be a rib-shaped protruding stopper on the surface of the cell holder, and the collision area can serve as a cutting line for the lead plate.

The above battery module has a simple structure in which the cell holder's positioning stopper is rib-shaped and the lead plate's cutting line is pressed against it, allowing the lead plate to be connected to the cell holder in the correct position. In particular, the above battery module uses the positioning stopper as a rib, and the lead plate's cutting line is pressed against it as a collision part to position the two in a fixed position. This eliminates the need to machine the lead plate into a special shape to create a protrusion, and allows for inexpensive mass production of lead plates that can be connected to the cell holder in the correct position, reducing manufacturing costs. Furthermore, because the lead plate's cutting line is pressed against the rib-shaped positioning stopper to position the two in the correct position, it has the advantage of allowing both to be positioned more accurately without deforming the collision part of the lead plate or the cell holder's positioning stopper.

A battery module according to another embodiment of the present invention is a cylindrical battery in which the battery cells have a central electrode in the center and peripheral electrodes on the outer periphery of the electrode end faces, and the lead plate can include a first connection lead welded to the peripheral electrode of the battery cell and a second connection lead welded to the central electrode of the battery cell.

In the above battery module, both the first and second connection leads are welded to one end surface of the cylindrical battery, eliminating the need to connect a lead plate to the bottom surface of the battery cell. This structure is effective in reducing the size of the battery module. Furthermore, a structure in which both the first and second connection leads are welded to one end surface requires high precision, particularly in the welding position of the first connection lead. This is because the peripheral electrode is narrow and the central electrode is located even closer. Misalignment of the welding position of the first connection lead prevents the connection lead from being securely welded, and if it comes into contact with the central electrode, it could cause a short circuit. The above structure, in which the lead plate and cell holder are positioned with high precision and the first connection lead is welded to the peripheral electrode, not only ensures stable welding, but also reliably prevents short circuits due to contact with the central electrode.

In another embodiment of the battery module of the present invention, the first connection lead of the lead plate is arm-shaped and extends tangentially to the peripheral electrode of the cylindrical battery, and the lead plate can be biased so that the first connection lead is displaced toward the center of the cylindrical battery.

In another embodiment of the battery module of the present invention, the collision portion is a cut line formed by cutting a metal plate in a straight line, the position control stopper is a rib-shaped stopper arranged parallel to the collision portion's cut line, and the first connection lead of the lead plate can be an arm-shaped stopper extending in a direction parallel to the collision portion's cut line and the position control stopper.

A battery module according to another embodiment of the present invention can be configured such that the lead plate has a bridge plate portion between the first connection lead and the collision portion, with a slit between the bridge plate portion and the first connection lead, the edge of the bridge plate portion facing the position restriction stopper being the cutting line of the collision portion, the cutting line of the collision portion and the first connection lead being arranged in a parallel position, and the first connection lead extending in the tangential direction of the peripheral electrode and welded to the peripheral electrode.

The above battery module has the advantage that the first connection lead can be positioned in a fixed position on the peripheral electrode with high precision and without misalignment, allowing it to be reliably welded without misalignment. This is because the lead plate uses one side edge of the bridge plate portion as a cutting line and the first connection lead is positioned on the other side edge via a slit, allowing the first connection lead and the cutting line to be positioned close to each other. The first connection lead, which is positioned close to the cutting line that positions the lead plate in an accurate position, is positioned in a fixed position at the cutting line and can be welded to the peripheral electrode without misalignment.

In another embodiment of the battery module of the present invention, the width of the bridge plate portion can be set to 20 mm or less.

In a battery module according to another embodiment of the present invention, the collision portion of the lead plate can be positioned at the base of the first connection lead. This battery module has the advantage of accurately positioning the first connection lead at the collision portion, preventing misalignment relative to the peripheral electrode and ensuring reliable welding. This is because the collision portion of the lead plate is positioned at the base of the rear end of the first connection lead, close to the welding portion.

In another embodiment of the battery module of the present invention, the lead plate can be a metal plate in which the first connection lead extending tangentially to the cylindrical battery is integrally formed with the lead plate body.

In another embodiment of the battery module of the present invention, the lead plates can be arranged so that the first connection lead and the second connection lead are perpendicular to each other.

In a battery module according to another embodiment of the present invention, the lead plate can have multiple elastic arm portions spaced apart in the width direction of the lead plate. This battery module has the advantage that each elastic arm portion presses against the cell holder, allowing the lead plate to move in parallel.

In a battery module according to another embodiment of the present invention, the lead plate can have multiple collision sections spaced apart in the width direction of the lead plate. This battery module has the advantage that the entire lead plate can be positioned in a fixed position.

In a battery module according to another embodiment of the present invention, the positioning stopper can be a rib-shaped stopper that protrudes from the surface of the cell holder and is molded as an integral structure. The above battery module has the advantage that the cell holder's positioning stopper is rib-shaped, and the lead plate can be connected to the cell holder in an accurate position with a simple structure in which the lead plate is pressed against this stopper.

In another embodiment of the battery module of the present invention, the opposing edges of the position restriction stopper and the collision portion can extend in a direction that intersects with the pressing direction of the elastic arm portion.

Specific examples of the present invention are described in detail below with reference to the drawings. In the following description, terms indicating specific directions or positions (e.g., "upper," "lower," and other terms incorporating these terms) are used as necessary. However, the use of these terms is intended to facilitate understanding of the invention with reference to the drawings, and the meaning of these terms does not limit the technical scope of the present invention. Furthermore, parts with the same reference numerals appearing in multiple drawings indicate the same or equivalent parts or components. Furthermore, the embodiments described below are illustrative examples of the technical concepts of the present invention, and do not limit the scope of the present invention to the following. Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described below are intended for illustrative purposes only, and are not intended to limit the scope of the present invention. Furthermore, the content described in one embodiment or example may also be applicable to other embodiments or examples. Furthermore, the size and positional relationships of components shown in the drawings may be exaggerated for clarity.

The battery module of the present invention is primarily suitable for use as an emergency power source or a power source for supplying power to the motor of an electric vehicle. However, the present invention does not specify the use of the battery module, and it can also be used as a power source for various other electrical devices.

(Embodiment 1)
In the battery module 100 shown in FIGS. 1 to 8, multiple battery cells 1 and lead plates 3 are positioned in fixed positions using cell holders 2 to form a battery assembly 10, which is then housed in an exterior case 4. The cell holders 2 arrange the multiple battery cells 1 in a parallel orientation with their electrode end surfaces 1A flush with one another. The electrode end surfaces 1A are where the positive and negative electrodes are located. Each battery cell 1 in the battery module 100 described above has a central electrode 1b and a peripheral electrode 1a on its electrode end surface 1A. One of the central electrode 1b and the peripheral electrode 1a is a positive electrode, and the other is a negative electrode. The central electrode 1b and the peripheral electrode 1a are connected in series or parallel by welding the connection leads 31 of the lead plates 3, which are positioned opposite the electrode end surfaces 1A. For ease of explanation of the present invention, FIGS. 2 to 12 below show the battery module shown in FIG. 1 in an inverted state.

(Battery Assembly 10)
The battery assembly 10 has cylindrical battery 1X cells 1 inserted into a cell holder 2 and arranged in multiple rows and columns in parallel orientation. The cell holder 2 positions the lead plates 3 facing the electrode end surfaces 1A of the battery cells 1.

(Battery cell 1)
Battery cell 1 has positive and negative electrodes on electrode end surfaces 1A. The battery cell 1 shown in the figure is a cylindrical battery 1X. Although not shown, cylindrical battery 1X has an electrode assembly housed in a cylindrical outer can 1B, which is filled with electrolyte and the opening of the outer can 1B is sealed with a sealing plate via an insulating material such as a gasket. The cylindrical battery 1X shown in Figure 2 has a central electrode 1b located in the center of the sealing plate insulated by the insulating material, and a peripheral electrode 1a located on the outer periphery of the outer can 1B.

Lithium-ion secondary batteries can be used for the battery cells 1. Lithium-ion secondary batteries have a high charge/discharge capacity relative to their weight and capacity. However, the present invention does not limit the battery cells 1 to lithium-ion batteries; currently used or future all-solid-state batteries and other secondary batteries can also be used. Furthermore, in the battery module 100 illustrated below, the battery cells 1 are cylindrical batteries 1X. However, the battery cells 1 are not limited to cylindrical batteries 1X; prismatic batteries and other types can also be used. The number of battery cells 1 is determined optimally based on the battery module's intended use, charge/discharge capacity, maximum load current, and capacity of each battery cell, and can be, for example, 10 to 100. The battery assembly 10 can increase the maximum current supplied to the load by connecting more battery cells 1 in parallel, and increase the total number of battery cells to increase the overall charge/discharge capacity. The battery module 100 shown in Figures 1 and 2 has 24 battery cells 1 arranged in parallel, with the electrode end surfaces 1A aligned on the same plane. The 24 battery cells are connected in parallel with six battery cells 1 via lead plates 3 to form parallel units, and adjacent parallel units are connected in series with lead plates 3, resulting in a 6-parallel, 4-series connection. However, the arrangement of the battery cells in a battery module is not limited to this and can be modified in various ways depending on the application and purpose. For example, as shown in Figure 13, 48 battery cells 1 can be connected in 12 parallel, 4 series, and the electrode end surfaces 1A of all battery cells 1 can be arranged in a parallel position with the same plane.

(Cell holder 2)
1 is composed of a main cell holder 2A that holds the battery cells 1 and lead plates 3 in place, a holding plate 2B that connects to the main cell holder 2A, and a cover plate 2C that closes the surface of the holding plate 2B. The main cell holder 2A and holding plate 2B can be made from thermoplastic resin such as plastic, which is an insulating material.

As shown in Figures 1 and 2, the main cell holder 2A has a surface plate 21 integrally molded and connected to the end of the holding section 50, into which each battery cell 1 is inserted and positioned. The main cell holder 2A shown in the figures is designed so that the ends of the battery cells 1 are inserted into multiple battery insertion sections 51 provided in the holding section 50 and positioned in a fixed position. The battery insertion sections 51 are cylindrical and fit along the outer periphery of the battery cells 1. The inner shape of the battery insertion sections 51 is approximately the same as the outer shape of the cylindrical batteries 1X, positioning the inserted cylindrical batteries 1X in a fixed position without misalignment. However, the cell holder is not limited to the above structure and can have any other structure that can hold multiple batteries in a fixed position.

The cell holder 2 shown in Figure 1 uses both the main cell holder 2A and the retaining plate 2B to position the battery cells 1 in their designated positions. The main cell holder 2A inserts the battery cells 1 into its cylindrical battery insertion section 51 and positions them in their designated positions, while the retaining plate 2B inserts the battery cells 1 into its through-holes 52 and positions them in their designated positions. The retaining plate 2B is connected to the main cell holder 2A and positions the battery cells 1 in their designated positions. The retaining plate 2B has through-holes 52 into which the ends of each cylindrical battery 1X are inserted. The inner diameter of the through-holes 52 is larger than the maximum tolerance of the outer diameter of the cylindrical battery 1X so as not to affect the positioning of the battery cells 1 inserted in the battery insertion section 51. With a cylindrical battery 1X inserted into the battery insertion section 51 of the main cell holder 2A, the retaining plate 2B is connected to the main cell holder 2A and positions each battery cell 1 in the cylindrical battery insertion section 51 of the main cell holder 2A and the through-holes 52 of the retaining plate 2B. A cover plate 2C is fixed to the outer surface of the holding plate 2B. The cover plate 2C is placed on the bottom surface of the cylindrical battery 1X, i.e., the surface opposite the electrode end surface 1A.

The main cell holder 2A in Figure 1 has an integral connecting tube 53 that connects to the holding plate 2B. The connecting tube 53 protrudes vertically from the holding portion 50 toward the holding plate 2B. The main cell holder 2A has multiple connecting tubes 53 at predetermined intervals along the outer periphery of the holding portion 50. The connecting tube 53 has a female threaded hole 53a on its upper end surface as shown in Figure 1. Set screws 54 are threaded into the female threaded hole 53a and penetrate the holding plate 2B, connecting the holding plate 2B to the main cell holder 2A. The holding plate 2B has an outer peripheral wall 55 around its periphery, which has a downward-protruding spacing rib portion 56. The spacing rib portion 56 creates a cooling gap between the outer peripheral wall 55 of the holding plate 2B and the outer peripheral wall 55 of the main cell holder 2A. This cell holder 2 can cool the battery cells 1 by blowing air into the cooling gap.

The cell holder 2 secures a cover plate 2C to the retaining plate 2B. The cover plate 2C is secured to the retaining plate 2B with set screws 58. The set screws 58 are threaded into threaded holes along the outer wall 55 of the retaining plate 2B or on the inside of the outer wall 55 to secure the cover plate 2C to the retaining plate 2B. The cover plate 2C is positioned away from the surface of the retaining plate 2B and supports the end faces of cylindrical batteries 1X inserted into the through holes 52 in the retaining plate 2B. This allows the cover plate 2C to hold multiple cylindrical batteries 1X while positioning their bottom surfaces flush with each other. The retaining plate 2B has an integral partitioning rib 57 that protrudes toward the inner surface of the cover plate 2C. The partitioning rib 57 can insulate adjacent battery cells 1 with a potential difference. This structure uses cylindrical batteries 1X with an electric potential on the exposed outer can 1B. These cylindrical batteries 1X are placed close to each other while maintaining a potential difference, and the partitioning rib 57 between them ensures reliable insulation.

The cover plate 2C can be made of insulating material such as plastic to reliably insulate the battery cells 1, but it can also be made of a metal plate. As shown in Figure 13, by sandwiching a thermally conductive sheet 7 with insulating properties between the metal cover plate 2C and the battery cells 1, it can also serve to efficiently dissipate heat generated by the battery cells 1 during charging and discharging.

The cell holder 2, which positions the battery cells 1 in fixed positions, also positions the lead plates 3 in fixed positions, preventing misalignment of the lead plates 3 relative to the battery cells 1 and accurately positioning the connection leads 31 of the lead plates 3 in positions opposite the electrodes of the battery cells 1. The cell holder 2 in Figures 2 to 7 has multiple lead plates 3 arranged on the outer surface of the surface plate 21 of the main cell holder 2A. The surface plate 21 arranges the multiple lead plates 3 at intervals in the longitudinal direction, and between adjacent lead plates 3, peripheral ribs 22 are integrally formed, which position the lead plates 3 (their outer edges) inward. The peripheral ribs 22 are located between adjacent lead plates 3 and can also be used as insulating ribs for the adjacent lead plates 3.

(Position restriction stopper 24)
The cell holder 2 is provided with positioning stoppers 24 that position each lead plate 3 in a fixed position to prevent misalignment due to dimensional errors during the manufacturing process and to position the lead plates 3 in a fixed position with high precision. The positioning stoppers 24 are provided on the surface plate 21 of the main cell holder 2A. The cell holder 2 shown in Figures 2 to 5 uses a portion of the peripheral rib 22, which is provided in a rib shape on the surface of the surface plate 21 of the main cell holder 2A, as the positioning stopper 24. This structure allows the positioning stopper 24 to be formed by the peripheral rib 22 that is provided to insulate adjacent lead plates 3, without the need for a separate dedicated positioning stopper.

The peripheral rib 22, part of which also serves as a positioning stopper 24, positions the lead plate 3 inside so that it can be displaced freely. The lead plate 3 shown in Figure 3 is placed in a mating recess 25 surrounded by the peripheral rib 22 and outer peripheral wall 23. The mating recess 25 positions the lead plate 3 so that it can be displaced freely. The inner shape of the mating recess 25 is slightly larger than the outer shape of the lead plate 3, and a displaceable gap is provided between the outer edge of the lead plate 3 and the inner surface of the mating recess 25, so that the lead plate 3 is positioned so that it can be displaced freely.

The battery module 100 described above has a simple structure in which the cell holder 2's positioning stopper 24 is rib-shaped and the lead plate 3's cutting line 33 is pressed against it, allowing the lead plate 3 to be accurately connected to the cell holder 2. In particular, the battery module 100 described above uses the positioning stopper 24 as a rib, with the lead plate 3's cutting line 33 pressed against it as a collision portion 34 to position the two in a fixed position. This eliminates the need to machine the lead plate 3 into a special shape to provide a protrusion, allowing for inexpensive mass production of lead plates 3 that can be connected to the cell holder 2 in a fixed position, reducing manufacturing costs. Furthermore, the lead plate 3's cutting line 33 is pressed against the rib-shaped positioning stopper 24 to position the two in a precise position, allowing for more accurate positioning without deforming the collision portion 34 of the lead plate 3 or the cell holder 2's positioning stopper 24.

(Connection mechanism 40)
Furthermore, the cell holder 2 in FIG. 3 displaceably connects the lead plate 3 via a connecting mechanism 40. The connecting mechanism 40 and the fitting recess 25 position the lead plate 3 on the cell holder 2 so that the collision portion 34, which is the cutting line 33 of the lead plate 3, can be displaced in a direction that brings the collision portion 34 closer to the position-regulating stopper 24 of the cell holder 2. The connecting mechanism 40 is structured to guide the insertion boss 42 of the cell holder 2 into the connecting hole 41 provided in the lead plate 3, and can be realized by providing a displacement gap 43 between the connecting hole 41 and the insertion boss 42 in the pressing direction of the elastic arm portion 35 described below. The connecting mechanism 40 described above has a simple structure that guides the insertion boss 42, which is the connecting protrusion of the cell holder 2, into the connecting hole 41 of the lead plate 3. This allows the lead plate 3 and the cell holder 2 to be displaceably connected, and restricts the displacement direction of the lead plate 3, guiding it in the intended direction for positioning. Furthermore, as described above, the structure in which the lead plate 3 is connected to the cell holder 2 in a freely displaceable manner allows the collision portion 34 of the lead plate 3 to be pressed against the position-regulating stopper 24 by the reaction force of the elastic arm portion 35 described below pressing against the cell holder 2, thereby allowing the lead plate 3 and cell holder 2 to be positioned accurately in the cell holder 2, thereby allowing efficient assembly while the lead plate 3 and cell holder 2 are connected.

In the above example, part of the peripheral rib 22 is used in combination with the position-regulating stopper 24. However, although not shown in the figures, the present invention also allows for a position-regulating stopper to be provided on the surface of the surface plate separately from the peripheral rib.

(Lead plate 3)
The lead plates 3 are set into the fitting recesses 25 inside the outer wall 23 and peripheral rib 22 of the cell holder 2 and connected to the battery cells 1. The lead plates 3 have connection leads 31 that are welded to the positive and negative electrodes of each battery cell 1. The connection leads 31 are connected by welding the welding portions at their tips to the battery cell 1 electrodes. Methods such as laser welding, spot welding, and ultrasonic welding can be used to weld the connection leads 31. Metal plates with good electrical and thermal conductivity are used for the lead plates 3. For example, metal plates such as iron plates with a nickel-plated surface, nickel plates, copper plates, and aluminum plates can be suitably used for the lead plates.

The lead plate 3 has connection leads 31 welded to the electrodes. The connection leads 31 are positioned opposite the battery cell 1 electrodes and welded to the electrodes. A single lead plate 3 has multiple connection leads 31 for connection to multiple battery cells 1. The lead plate 3 shown in Figures 2 to 7 has multiple connection leads 31 formed by cutting a portion of a metal plate. This lead plate 3 has slits 32 between the connection leads 31 and the plate-shaped main plate portion 30, separating the connection leads 31 from the main plate portion 30 and connecting the rear ends of the connection leads 31 to the main plate portion 30. The connection leads 31 are arm-shaped, extending from the main plate portion 30 toward their tip, and their tips are welded. The lead plate 3 has a second connection lead 31b that connects to the central electrode 1b of the battery cell 1 and a first connection lead 31a that connects to the peripheral electrode 1a. The second connection lead 31b is positioned so that it extends in the radial direction of the cylindrical battery 1X, and the first connection lead 31a is positioned so that it extends in the tangential direction of the circular peripheral electrode 1a located on the outer periphery of the cylindrical battery 1X. The lead plates 3 in Figures 6 and 7 are positioned so that the first connection lead 31a and second connection lead 31b are perpendicular to each other, with the first connection lead 31a extending in the tangential direction of the cylindrical battery 1X and the second connection lead 31b extending in the radial direction of the cylindrical battery 1X.

(Structure for arranging lead plate 3 in fixed position in cell holder 2)
The cell holder 2 positions the lead plates 3 in fixed positions, which are welded to the electrodes of the battery cells 1. The cell holder 2 is provided with positioning stoppers 24 to position the lead plates 3 in fixed positions. The lead plates 3 are pressed against the positioning stoppers 24 to be positioned in fixed positions, and the connection leads 31 are welded to the electrodes of the battery cells 1. The lead plates 3 are equipped with elastic arm portions 35 that elastically press against the cell holder 2. The lead plates 3 are pressed against the positioning stoppers 24 as a reaction to the elastic arm portions 35 pressing against the cell holder 2, and are positioned in their fixed positions on the cell holder 2.

The elastic arm portion 35 shown in Figures 2 to 7 utilizes the external shape of the lead plate 3 to create a bent or folded spring shape, guiding the lead plate 3 in one direction. The lead plate 3 shown in Figure 3 has an elastic arm portion 35 on its right edge that presses against the outer wall 23 or peripheral rib 22 of the cell holder 2. The elastic arm portion shown in the figure is formed by bending a metal piece protruding from the main plate portion 30. The elastic arm portion 35 of this structure can be easily formed by cutting a metal plate into a predetermined shape to form the lead plate 3, and then bending the protruding piece protruding from the main plate portion 30. The lead plate 3 shown in the figure has elastic arm portions 35 on both ends of the right edge of the main plate portion 30. With this structure, multiple elastic arm portions 35 simultaneously press against the outer wall 23 or peripheral rib 22 of the cell holder 2, allowing the reaction force to stably displace the lead plate 3 in the predetermined direction.

However, the shape, width, thickness, number, structure, configuration, and placement location of the elastic arm portion 35 are not limited. For example, it can be bent or folded in various shapes, or it can be left unfolded. Furthermore, as shown in Figures 9 to 12, which will be described later, the elastic arm portion 35 and the connecting mechanism 40 can be integrated to provide both elastic force for pressing and positioning. Furthermore, although not shown, it is also possible to provide a convex portion on the cell holder side and a shape or structure in which the cell holder is received by a concave portion on the elastic arm portion.

The lead plate 3 also has a collision portion 34 that collides with the position-regulating stopper 24 of the cell holder 2, positioning it in a fixed position. When the collision portion 34 of the lead plate 3 approaches the cell holder 2 and abuts against the position-regulating stopper 24, it acts as a stopper to regulate the position and hold it in the intended, predetermined position. As mentioned above, the lead plate 3 is set in the cell holder 2 with a displaceable gap between it and the cell holder 2, so that the lead plate 3 moves relative to the cell holder 2 in reaction to the elastic arm portion 35 pushing against the cell holder 2, and is positioned in a fixed position when the collision portion 34 abuts against the position-regulating stopper 24.

The lead plate 3 in Figure 3 has a collision section 34 defined by a linear cut line 33 on the outer edge of the metal plate, and the positioning stopper 24 has a rib shape parallel to the cut line 33 at the collision section 34. Furthermore, the first connection lead 31a on the lead plate 3 is arm-shaped and extends tangentially to the peripheral electrode 1a of the cylindrical battery 1X. The elastic arm section 35 elastically presses the lead plate 3 in the radial direction of the cylindrical battery 1X, with the first connection lead 31a directed toward the center of the cylindrical battery 1X. This structure urges the lead plate 3 in the radial direction of the cylindrical battery 1X as a reaction to the elastic arm section 35 pressing against the cell holder 2, preventing misalignment in this direction between the lead plate 3 and the cell holder 2 and positioning the first connection lead 31a without misalignment in the radial direction of the cylindrical battery 1X. This structure allows the first connection lead 31a to be reliably welded to the peripheral electrode 1a in a position extending tangentially to the peripheral electrode 1a without contacting the central electrode 1b. This is because the collision portion 34 is the linear cutting line 33, the positioning stopper 24 is a rib-shaped stopper parallel to the cutting line 33, and the first connection lead 31a is arm-shaped extending in a direction parallel to the cutting line 33. This allows the cutting line 33 and the positioning stopper 24 to abut linearly over a predetermined length, positioning the lead plate 3 accurately on the cell holder 2, particularly preventing misalignment of the first connection lead 31a in the width direction, allowing the first connection lead 31a to be reliably welded to the peripheral electrode 1a of the cylindrical battery 1X without misalignment.

The lead plate 3 preferably has multiple elastic arm portions 35 spaced apart in the width direction. This lead plate 3 has the advantage that each elastic arm portion 35 presses against the cell holder 2, allowing the lead plate 3 to move in parallel. Furthermore, the lead plate 3 preferably has multiple collision portions 34 spaced apart in the width direction. This lead plate 3 has the advantage that each collision portion 34, spaced apart in the width direction of the lead plate 3, can be positioned in a fixed position by a positioning stopper 24, allowing the entire lead plate 3 to be positioned in a fixed position. The lead plate 3 in Figure 3 has elastic arm portions 35 on both sides in the width direction, and collision portions 34 on both sides in the width direction. This lead plate 3 has the advantage that each elastic arm portion 35 presses against the cell holder 2, allowing the lead plate 3 to move in parallel, and the parallel-moving lead plate 3 can be positioned in a fixed position by the collision portions 34 on both sides, allowing the entire lead plate 3 to be positioned in a fixed position with high precision.

Furthermore, the lead plate 3 in Figures 2 to 7 has a bridge plate portion 36 on part of the main plate portion 30. The bridge plate portion 36 is located between the cutting line 33 of the collision portion 34 and the first connection lead 31a. A slit 32 is provided between the bridge plate portion 36 and the first connection lead 31a. The connection lead 31 has a base portion 37 connected to the main plate portion 30 and a slit 32 around its periphery. The connection lead 31 can be welded by moving the welding portion toward the electrode end surface 1A of the battery cell 1. The edge of the bridge plate portion 36 facing the position restriction stopper 24 is the cutting line 33 of the collision portion 34, and the position restriction stopper 24, cutting line 33, and first connection lead 31a are positioned parallel to each other. The first connection lead 31a extends tangentially to the peripheral electrode 1a of the cylindrical battery 1X, and the welding portion at its tip is welded to the peripheral electrode 1a. The width (W) of the bridge plate portion 36 is, for example, 20 mm or less, preferably 15 mm or less, and even more preferably 10 mm or less, allowing the first connection lead 31a to be positioned more accurately and without misalignment with the peripheral electrode 1a of the cylindrical battery 1X.

The above structure has the advantage that the first connection lead 31a can be positioned opposite the peripheral electrode 1a with high precision and without misalignment, ensuring reliable welding. This is because the first connection lead 31a is positioned close to the cutting line 33 of the collision portion 34 via the bridge plate portion 36, and the first connection lead 31a, which extends tangentially to the peripheral electrode 1a, and the cutting line 33 of the collision portion 34 are positioned parallel to each other, ensuring that the collision portion 34 of the cutting line 33 reliably prevents the first connection lead 31a from misaligning in the radial direction of the cylindrical battery 1X.

Furthermore, as shown in Figure 8, the collision portion 34 of the lead plate 3 is positioned at the base 37 of the first connection lead 31a, and this collision portion 34 abuts against the positioning stopper 24 on the wall that regulates the position, allowing the first connection lead 31a to be positioned in a predetermined position. This is because the base 37 is closer to and more directly connected to the first connection lead 31a, and the collision portion 34 of the cutting line 33 reliably prevents the first connection lead 31a from shifting radially from the cylindrical battery 1X.

The connecting mechanism 40, shown in the enlarged views of key parts in Figures 4 and 6, consists of a connecting hole 41 that is elongated in the displacement direction and penetrates the lead plate 3, and an insertion boss 42 that protrudes from the surface plate 21 of the cell holder 2. A displacement gap 43 is provided between the connecting hole 41 and the insertion boss 42 in the direction in which the collision portion 34 approaches the positioning stopper 24 and in the pressing direction of the elastic arm portion 35. This allows the collision portion 34 of the lead plate 3 to move toward the positioning stopper 24, thereby connecting the lead plate 3 to the cell holder 2 in a displaceable manner. This connecting mechanism 40 has a simple structure in which the insertion boss 42 is molded integrally with the cell holder 2 and a connecting hole 41 is provided through the lead plate 3, allowing the lead plate 3 and cell holder 2 to be displaceable in the pressing direction of the elastic arm portion 35. The connecting mechanism 40 restricts the displacement direction of the lead plate 3, guiding and positioning the lead plate 3 in the intended direction.

As described above, this structure, which provides a mating recess 25 in the cell holder 2 and further connects the lead plate 3 and cell holder 2 in a displaceable manner using a connecting mechanism consisting of a connecting hole and insertion boss, allows the lead plate 3 to be easily set in a predetermined position on the cell holder 2, and then the elastic arm 35 presses against the cell holder 2, positioning the lead plate 3 in its fixed position on the cell holder 2, resulting in efficient assembly.

The connecting mechanism 40 is designed to insert the insertion boss 42 of the cell holder 2 into the connecting hole 41 provided in the lead plate 3. This can be achieved by providing a displacement gap 43 between the connecting hole 41 and the insertion boss 42 in the pressing direction of the elastic arm portion 35. The above connecting mechanism 40 has a simple structure in which the insertion boss 42 of the cell holder 2 is inserted into the connecting hole 41 of the lead plate 3, and can displaceably connect the lead plate 3 and the cell holder 2. Furthermore, the structure described above, which displaceably connects the lead plate 3 to the cell holder 2, is urged in the opposite direction by the reaction of the elastic arm portion 35 (described below) pressing against the cell holder 2, pressing the lead plate 3 against the positioning stopper 24 and accurately positioning the cell holder 2. This allows for efficient assembly when the lead plate 3 and cell holder 2 are connected.

As described above, the displacement direction of the lead plate 3 can be restricted by the connecting mechanism 40, which consists of the elongated connecting hole 41 and insertion boss 42. Furthermore, the connecting mechanism 40 can also be configured with the peripheral rib 22, outer wall 23, and the cutting line or side edge of the lead plate 3 that moves along these to specify the displacement direction of the lead plate 3. For example, as shown in Figure 3, the connecting mechanism 40 can use left and right guide walls 27 formed from parts of the peripheral rib 22 that are arranged parallel to the pressing direction of the elastic arm portion 35. The left and right guide walls 27 can be used in place of the connecting mechanism 40, or in combination with it.

(Embodiment 2)
The battery module 200 in FIGS. 9 to 12 shows a specific example in which the shape and structure of the lead-plate 3 connected to the cell holder 2 are different. This embodiment can be similar to the first embodiment except for the shape and structure of the lead-plate 3 connected to the cell holder 2. This lead-plate 3 differs from the first embodiment in the structure of the elastic arm 35 that elastically presses against the cell holder 2. The elastic arm 35 of the lead-plate 3 shown in FIGS. 9 to 11 is a leaf spring with a protruding piece that protrudes inward from the edge of the connecting hole 45 opened in the main plate 30. With this structure, the lead-plate 3 guides the insertion boss 42 of the cell holder 2 into the connecting hole 45, and the elastic arm 35, which is a leaf spring with a protruding piece, presses against the insertion boss 42. The lead-plate 3 is urged in the opposite direction by the reaction of the elastic arm 35 pressing against the insertion boss 42, displacing toward the position restriction stopper 24. As a result, the collision portion 34 of the lead plate 3 approaches the position restriction stopper 24, and the collision portion 34 comes into contact with the position restriction stopper 24 while being pressed against it, thereby positioning the lead plate 3.

The elastic arm portion 35a in FIG. 9 elastically presses against one surface of the insertion boss 42 guided into the connecting hole 45, urging the lead plate 3 in the direction of displacement. Therefore, the lead plate 3 in this figure, with the elastic arm portion 35a and connecting mechanism 40 integrated, connects the lead plate 3 to the cell holder 2 in a freely displaceable manner. The elastic arm portion 35a urges the collision portion 34 of the lead plate 3 in a direction pressing it against the positioning stopper 24. The elastic arm portion 35a in FIG. 9 urges the lead plate 3 in a direction perpendicular to the collision portion 34 and the positioning stopper 24, which are linear and arranged in parallel. The elastic arm portion 35a in FIG. 9 elastically presses against one surface of the insertion boss 42 guided into the connecting hole 45, urging the lead plate 3 in the direction of displacement. The connecting hole 45 in FIG. 9 is tapered in one direction so that the lead plate 3 can be guided toward the intended predetermined position, thereby functioning as the connecting mechanism 40.

The shape, width, thickness, etc. of the elastic arm portion 35 protruding into the connecting hole 45 can be appropriately determined depending on the elastic force and the direction of pressure. Multiple elastic arm portions 35 can be provided protruding into one connecting hole 45. Figure 10 shows three elastic arm portions 35b, 35c, and 35d pressing against one connecting hole 45 with elastic forces from three directions. In Figure 10, elastic arm portion 35b presses in the same elastic direction as elastic arm portion 35a in Figure 9. Furthermore, elastic arm portions 35c and 35d press from the left and right in a direction perpendicular to the elastic direction of elastic arm portion 35b, sandwiching the insertion boss 42 and preventing left-right misalignment. When multiple elastic arm portions 35 are provided, each elastic arm portion 35 can have a different elastic force. For example, the elastic arm portion 35b in Figure 10 can provide a stronger elastic pressing force than the secondary elastic arm portions 35c and 35d, which suppress left-right misalignment. In Figure 11, two elastic arms 35e and 35f press against one connecting hole 41 with elastic forces from two directions. Elastic arms 35e and 35f press in the same elastic direction as elastic arm portion 35a in Figure 9, while also restricting left-right movement.

As shown in Figures 9 to 11, even when the elastic arm portion 35 and connecting mechanism 40 are integrated to connect the lead plate 3 to the cell holder 2 in a displaceable manner, preferably multiple connecting mechanisms 40 are arranged spaced apart in the width direction of the lead plate 3, and the cell holder 2 and lead plate 3 are connected via these connecting mechanisms 40. Multiple connecting holes 45 and elastic arm portions 35 are arranged in the lead plate 3, and multiple insertion bosses 42 are arranged in the cell holder 2, each spaced apart in the width direction of the lead plate 3. Note that the connecting mechanism 40 of embodiment 1 shown in Figures 3 to 7 and the positioning connecting mechanism 40 of embodiment 2 can be used together. Furthermore, the elastic arm portion 35 that utilizes the outer shape of the lead plate 3 of embodiment 1 and the elastic arm portion 35 shown in Figure 12 can also be used together.

The elastic arm portion 35 shown in Figures 9 to 11 is a leaf spring and is configured to elastically press against the insertion boss 42 guided in the connecting hole 45, thereby pressing against the cell holder 2. However, the leaf spring-like elastic arm portion 35 is not limited to a structure that presses against the insertion boss 42 guided in the connecting hole 45. The lead plate 3 shown in Figure 12 has a leaf spring-like elastic arm portion 35g on its outer periphery, and the cell holder 2 has a convex portion 28 that protrudes from the outer periphery wall 23 or peripheral rib 22 toward the mating recess 25, and this convex portion 28 is pressed by the elastic arm portion 35g. The lead plate 3 shown in the figure has a concave portion 38 on its outer periphery that guides the convex portion 28 of the cell holder 2, and is configured to elastically press against the convex portion 28 by the elastic arm portion 35g, which is a protruding piece provided inside the concave portion 38. The protrusion 28 shown in Figure 12 has an extension 28a that extends in the displacement direction of the lead plate 3 in a plan view, and a semicircular curved portion 28b connected to the tip of this extension 28a. The lead plate 3 has a resilient arm 35g located inside the recess 38 that guides the protrusion 28, facing the curved portion 28b, and pressing against the protrusion 28. This resilient arm 35g presses the protrusion 28 in the extension direction of the extension 28a, and in reaction to this, urges the lead plate 3 in the opposite direction, displacing the lead plate 3 in the specified direction.

The battery module of the present invention can be suitably used as a rechargeable battery module for battery-powered devices such as assisted bicycles, electric motorcycles, electric wheelchairs, electric carts, cleaners, and power tools.

100, 200... battery module 1... battery cell 1X... cylindrical battery 1A... electrode end surface 1B... outer can 1a... peripheral electrode 1b... central electrode 2... cell holder 2A... main cell holder 2B... holding plate 2C... cover plate 3... lead plate 4... outer case 7... thermally conductive sheet 10... battery assembly 21... surface plate 22... peripheral rib 23... outer peripheral wall 24... position regulation stopper 25... fitting recess 27... guide wall 28... protrusion 28a... extension portion 28b... curved portion 30... main plate portion 31... connection Connection lead 31a...first connection lead 31b...second connection lead 32...slit 33...cutting line 34...collision portion 35, 35a, 35b, 35c, 35d, 35e, 35f, 35g...elastic arm portion 36...bridge plate-shaped portion 37...base portion 38...recess 40...connecting mechanism 41...connecting hole 42...insertion boss 43...displacement gap 50...holding portion 51...battery insertion portion 52...through hole 53...connecting tube 53a...female threaded hole 54...set screw 55...outer peripheral wall 56...spacing rib portion 57...partition rib 58...set screw

Claims (14)

A plurality of battery cells;
a lead plate formed by welding a connection lead to an electrode of the battery cell;
a cell holder that connects the battery cell and the lead plate;
the cell holder includes a position-regulating stopper for locating the lead plate in a fixed position;
The lead plate is
an elastic arm portion that elastically presses the cell holder;
a collision portion that is biased by a reaction force of the elastic arm portion pressing the cell holder and abuts against the position restriction stopper,
Furthermore, the lead plate is disposed in the cell holder so as to be displaceable in a direction in which the collision portion approaches the position regulating stopper,
the lead plate is displaced by a reaction force of the elastic arm portion pressing against the cell holder, and the collision portion of the lead plate abuts against the position regulating stopper, so that the lead plate is arranged at a fixed position in the cell holder ,
the cell holder and the lead plate are connected via a connecting mechanism that can displace the relative positions of the cell holder and the lead plate in a direction that brings the collision portion closer to the position regulating stopper,
The coupling mechanism is
a connecting hole formed in the lead plate;
an insertion boss provided on the cell holder and inserted into the connecting hole;
The battery module has a displacement gap provided between the connecting hole and the insertion boss in a direction that allows the collision portion to approach the position restriction stopper. The battery module according to claim 1 ,
The position-regulating stopper has a rib shape that protrudes from the surface of the cell holder,
The battery module, wherein the collision portion is a cutting line of the lead plate. The battery module according to claim 1 or 2 ,
The battery cell is a cylindrical battery having a central electrode in the center and a peripheral electrode on the outer periphery of the electrode end surface,
The lead plate is
a first connection lead welded to a peripheral electrode of the battery cell;
a second connection lead welded to the central electrode of the battery cell;
A battery module comprising: The battery module according to claim 3 ,
The first connection lead of the lead plate has an arm shape extending in a tangential direction of the peripheral electrode of the cylindrical battery,
The battery module is configured such that the lead plate is biased so that the first connection lead is displaced toward the center of the cylindrical battery. The battery module according to claim 3 or 4 ,
The collision portion is
A cutting line made by cutting a metal plate in a straight line.
The position restriction stopper is
A rib shape arranged parallel to the cutting line of the collision portion,
The first connection lead of the lead plate is
The battery module has an arm shape extending in a direction parallel to the cutting line of the collision portion and the position restriction stopper. The battery module according to claim 5 ,
The lead plate is
a bridge plate-shaped portion is provided between the first connection lead and the collision portion,
a slit is provided between the bridge plate portion and the first connection lead;
The bridge plate-shaped portion is
The edge facing the position regulating stopper is set as the cutting line of the collision portion,
the cutting line of the collision portion and the first connection lead are arranged in a parallel orientation to each other,
The first connection lead extends in a tangential direction of the peripheral electrode and is welded to the peripheral electrode. The battery module according to claim 6 ,
A battery module in which the width of the bridge plate-shaped portion is 20 mm or less. The battery module according to any one of claims 3 to 7 ,
a base portion of the first connection lead;
The battery module in which the collision portion of the lead plate is arranged. The battery module according to any one of claims 3 to 8 ,
The lead plate is a metal plate integrally provided with the first connection lead extending in the tangential direction of the cylindrical battery. The battery module according to any one of claims 3 to 9 ,
The lead plate is
a battery module in which the first connection lead and the second connection lead are provided in directions perpendicular to each other; The battery module according to any one of claims 1 to 10 ,
The lead plate is
The battery module includes a plurality of elastic arm portions spaced apart in the width direction of the lead plate. The battery module according to any one of claims 1 to 11 ,
The lead plate is
The battery module includes a plurality of the collision portions spaced apart in the width direction of the lead plates. The battery module according to any one of claims 1 to 12 ,
The position restriction stopper is
The battery module has ribs formed integrally with the cell holder so as to protrude from the surface. The battery module according to any one of claims 1 to 13 ,
The position restriction stopper and the opposing edge of the collision portion are
The battery module extends in a direction intersecting the pressing direction of the elastic arm portion.