Battery pack and method for manufacturing same

Abstract

The present invention makes it easy to connect a circuit board and a battery pack. A battery pack (100) is provided with: a battery holder (20) that holds a plurality of secondary battery cells (1) and a plurality of lead plates (30); a circuit board (40) having a rectangular shape having a pair of end edges and a pair of side surfaces intersecting the pair of end edges, the circuit board (40) having a plurality of electrical connection regions (42) for connecting to the plurality of lead plates (30), respectively; and a pair of guide walls (23) that form, on one surface of the battery holder (20), slots (28) into which the circuit board (40) is inserted, the slots (28) respectively guiding a pair of side surfaces of the circuit board (40). The plurality of lead plates (30) are provided with bent pieces (32), and the bent pieces (32) are connected with the electric connection areas (42) of the circuit substrate (40) in a bent mode. When the circuit board (40) is inserted into the slot (28), each of the plurality of electrical connection regions (42) is connected to the bent piece (32), and the plurality of lead plates (30) are electrically connected to the circuit board (32).

Description

Technical Field

[0001] The present disclosure relates to a battery pack and a method for manufacturing the same. Background Art

[0002] In order to drive an electrical device using a rechargeable secondary battery such as a lithium ion secondary battery, a battery pack (for example, Patent Document 1) that houses a plurality of secondary battery cells in an outer casing is used. In such a battery pack, a battery holder that houses the secondary battery cells and a circuit board on which a charge / discharge circuit, a protection circuit, etc. of the secondary battery cells are mounted are provided. In addition, a plurality of secondary battery cells are connected in series and in parallel through a lead plate that is a metal plate. Further, the plurality of secondary battery cells are electrically connected to the circuit board so that the intermediate potential and the total potential of the plurality of secondary battery cells can be detected through the circuit board.

[0003] However, there is a problem that it takes time to fix such a circuit board to the battery holder. For example, in the case of connecting a plurality of secondary battery cells in series, in order to detect the intermediate potential, it is necessary to electrically connect a plurality of lead plates to the circuit board respectively. Therefore, there is a problem that operations of connecting leads, lead pins, etc. led out from the lead plate to the circuit board are required, and not only the structure becomes complicated but also the assembly process becomes complicated.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2013-247100 Summary of the Invention

[0007] -Problems to be Solved by the Invention-

[0008] One object of the present disclosure is to provide a battery pack and a method for manufacturing the same that can easily connect a circuit board to the battery pack.

[0009] -Means for Solving the Problems-

[0010] A battery pack according to one aspect of the present disclosure includes: a plurality of secondary battery cells; a plurality of lead plates that connect the plurality of secondary battery cells in series and / or in parallel; a battery holder that holds the plurality of secondary battery cells and the plurality of lead plates; a circuit board that is rectangular with a pair of end edges and a pair of side surfaces intersecting the pair of end edges, and has a plurality of electrical connection regions for connecting to the plurality of lead plates respectively; and a pair of guide walls that form a slot on one surface of the battery holder for inserting the circuit board, the slot guiding the pair of side surfaces of the circuit board respectively, and the plurality of lead plates having bent pieces that are connected to the electrical connection regions of the circuit board in a bent form, and in a state where the circuit board is inserted into the slot, connecting the bent pieces to the plurality of electrical connection regions respectively and electrically connecting the plurality of lead plates to the circuit board.

[0011] In addition, in a method for manufacturing a battery pack according to another aspect of the present disclosure, the battery pack includes: a plurality of secondary battery cells; lead plates that are a plurality of lead plates for connecting the plurality of secondary battery cells in series and / or in parallel, and are formed by bending bent pieces in advance; a battery holder that holds the plurality of secondary battery cells and the plurality of lead plates; and a circuit board that is rectangular with a pair of end edges and a pair of side surfaces intersecting the pair of end edges, and has a plurality of electrical connection regions for connecting to the plurality of lead plates respectively. The method for manufacturing the battery pack includes: a step of fixing the covering surfaces of the plurality of lead plates on a pair of assembly side surfaces of a battery assembly where the end surfaces of the respective secondary battery cells are exposed in the same plane, the battery assembly being formed in a state where the plurality of secondary battery cells accommodated in the battery holder are stacked; a step of inserting the circuit board into a slot formed on one surface of the battery holder and freely slidably divided by guiding the pair of side surfaces of the circuit board by respective guide walls, and opposing the bent pieces of the respective lead plates to the plurality of electrical connection regions; and a step of connecting each bent piece to each battery connection region.

[0012] -Advantages of the Invention-

[0013] According to the battery pack according to one aspect of the present disclosure, the circuit board can be assembled to the battery holder by inserting the circuit board along the guide wall into the slot, and position alignment for electrically connecting the lead plate and the circuit board can be performed. Description of the Drawings

[0014] Figure 1 is a perspective view showing a battery pack according to Embodiment 1.

[0015] Figure 2 is a Figure 1 exploded perspective view of the outer housing.

[0016] Figure 3 is a perspective view of the battery holder shown Figure 2 below.

[0017] Figure 4 is Figure 3 a top view of the battery holder shown

[0018] Figure 5 is Figure 4 a longitudinal sectional view of the battery holder shown

[0019] Figure 6 is an exploded perspective view of the battery holder with the circuit board removed from Figure 3 the battery holder shown

[0020] Figure 7 is Figure 6 an exploded perspective view of the battery holder shown

[0021] Figure 8 is a perspective view of the lead plate

[0022] Figure 9 is Figure 2 a sectional perspective view of the battery pack shown

[0023] Figure 10 a perspective view of the battery pack related to the comparative example shown

[0024] Figure 11 is an exploded perspective view of the battery pack related to another comparative example shown

[0025] Figure 12 is a perspective view of the process of bending the lead plate of the battery pack shown Figure 11 below

[0026] Figure 13 is Figure 4 a sectional perspective view of the battery holder shown

[0027] Figure 14 is Figure 6 a transverse sectional view of the battery holder shown

[0028] Figure 15 is Figure 4 a transverse sectional view of the battery holder shown

[0029] Figure 16 is a transverse sectional view of the battery pack related to Embodiment 2

[0030] Figure 17 is a perspective view of the process of bending the lead plate of the battery pack shown Figure 16Longitudinal sectional view of the state where the circuit board of the battery pack is inserted into the slot of the battery holder.

[0031] Figure 18 It is a longitudinal sectional view showing the state where the circuit board of the battery pack according to the modified example is inserted into the slot of the battery holder. Detailed Description

[0032] The mode of the present disclosure can also be determined by the following structures and features.

[0033] Regarding the battery pack according to another mode of the present disclosure, in the above mode, the plurality of secondary battery cells are cylindrical with different electrodes on a pair of end faces, the plurality of lead plates each have a covering surface, and the covering surface partially covers a pair of aggregate side faces of the battery aggregate formed by laminating the plurality of secondary battery cells, where the end faces of the respective secondary battery cells are exposed in the same planar shape, and the bent pieces project from the covering surface in a bent manner, and the bent pieces are connected to the electrical connection regions of the circuit board. With the above structure, since the circuit board can be inserted into the slot in a state where the bent pieces of the lead plate are pre-bent and the respective bent pieces are fixed to the electrical connection regions, it is possible to easily perform position alignment for the electrical connection between the lead plate and the circuit board.

[0034] In addition, regarding the battery pack according to another mode of the present disclosure, in any of the above modes, the battery holder includes a battery accommodation portion for accommodating the plurality of secondary battery cells, and the circuit board is assembled on the upper surface of the battery accommodation portion.

[0035] Furthermore, regarding the battery pack according to another mode of the present disclosure, in any of the above modes, the guide wall is integrally formed with the battery holder.

[0036] Furthermore, in addition, regarding the battery pack according to another mode of the present disclosure, in any of the above modes, the guide wall includes a guide L portion formed in an L shape so as to cover from a pair of side faces to the upper surface of the circuit board, and a lead window for exposing the bent pieces is opened in the guide L portion. With the above structure, by exposing the bent pieces of the lead plate from the lead window in a state where the circuit board is inserted into the slot, fixing operations such as welding can be performed in the electrical connection regions.

[0037] Furthermore, in addition, regarding the battery pack according to another mode of the present disclosure, in any of the above modes, the battery pack further includes: an assembly portion that covers the other end edge of the circuit board in a state where the circuit board is inserted into the slot. With the above structure, the circuit board can be inserted into the slot, and one end edge of the circuit board can be brought into contact with the assembly portion for positioning.

[0038] Further, regarding the battery pack according to another aspect of the present disclosure, in any of the above aspects, the fitting portion is formed in a eaves shape protruding from the upper surface of the battery housing portion, and the battery pack is configured such that, in a state where the circuit board is inserted into the slot, from the other end edge of the circuit board to a part of the upper surface, the circuit board is covered by the eaves-shaped fitting portion. With the above structure, the circuit board can be held by clamping the end edge with the eaves-shaped fitting portion.

[0039] Further, regarding the battery pack according to another aspect of the present disclosure, in any of the above aspects, the bent pieces of the respective lead plates are elastically bent from the covering surface. With the above structure, it is possible to easily connect the lead plates to the electrical connection regions of the circuit board in a state where the circuit board is inserted along the guide wall and assembled to the battery holder.

[0040] Further, regarding the battery pack according to another aspect of the present disclosure, in any of the above aspects, the angle at which the bent pieces of the respective lead plates are bent with respect to the covering surface is 70° to 90°.

[0041] Further, regarding the battery pack according to another aspect of the present disclosure, in any of the above aspects, the plurality of electrical connection regions include: an intermediate potential connection region that is connected to any one of the plurality of lead plates and detects the intermediate potential of the plurality of secondary battery cells; and a total potential connection region that is connected to any other one of the plurality of lead plates and detects the total potential of the plurality of secondary battery cells.

[0042] Further, regarding the method for manufacturing a battery pack according to another aspect of the present disclosure, in any of the above aspects, the step of inserting the circuit board into the slot and bringing the bent pieces into confrontation with the plurality of electrical connection regions includes the following steps: bringing the end edge of the circuit board into contact with the fitting portion provided to intersect the pair of guide walls, and positioning the relative position of the circuit board and the battery holder so that the electrical connection regions and the bent pieces are in an overlapping position. Thereby, it is possible to easily position the circuit board and the battery holder so that the bent pieces and the electrical connection regions are in an overlapping posture.

[0043] Furthermore, regarding the method for manufacturing a battery pack according to another aspect of the present disclosure, in any of the above aspects, in the step of inserting the circuit board between the pair of guide walls, the upper ends of the plurality of lead plates are elastically bent at a position above the trajectory of inserting the circuit board between the pair of guide walls. In the step of electrically connecting the plurality of electrical connection regions in the overlapped state to the lead plates, the upper ends of the respective lead plates are crimped to the respective electrical connection regions by a jig. Thereby, each lead plate can be simply electrically connected to the circuit board.

[0044] Furthermore, regarding the method for manufacturing a battery pack according to another aspect of the present disclosure, in any of the above aspects, the bent pieces of each lead plate are bent relative to the covering surface by 70° to 90°.

[0045] Hereinafter, embodiments of the present disclosure will be described based on the drawings. However, the embodiments shown below are examples for embodying the technical idea of the present disclosure, and the present disclosure is not limited to the following content. In addition, this specification does not limit the components shown in the claims to the components of the embodiments. In particular, the dimensions, materials, shapes, relative arrangements, etc. of the structural components described in the embodiments are not intended to limit the scope of the present disclosure thereto as long as there is no specific description, and are merely illustrative examples. In addition, for clarity of explanation, the sizes, positional relationships, etc. of the components shown in the respective drawings are sometimes exaggerated. Furthermore, in the following description, for the same names and symbols, the same or homogeneous components are indicated, and detailed descriptions are appropriately omitted. Further, each element constituting the present disclosure may be a mode in which a plurality of elements are constituted by the same component and thus one component serves as a plurality of components, and conversely, the function of one component can also be realized by sharing it among a plurality of components.

[0046] The battery pack of the present disclosure can be used as a driving power source for a power-assisted bicycle, an electric scooter for delivery, etc., an electric cart for a golf course, a factory, an airport, etc., a power source for an autonomous mobile robot for delivery, a construction machine, a hybrid vehicle, a driving power source for a vehicle such as an electric vehicle, etc. In addition, it can also be used as a power source for portable electrical devices such as a wireless communication device, an electric cleaner, and an electric tool. Or it can also be used as a standby power source for a server, a power supply device for home, office, and factory in a stationary energy storage application. Hereinafter, as an embodiment of the present disclosure, a battery pack used as a driving power source for a power-assisted bicycle will be described.

[0047] [Embodiment 1]

[0048] The battery pack 100 according to Embodiment 1 of the present disclosure is shown in Figures 1 to 9 . In these figures, respectively, Figure 1A perspective view showing the battery pack 100 according to Embodiment 1 is shown. Figure 2 A perspective view showing the Figure 1 outer housing 10 disassembled is shown. Figure 3 A perspective view showing the Figure 2 battery holder 20 is shown. Figure 4 A top view showing the Figure 3 battery holder 20 is shown. Figure 5 A longitudinal sectional view taken along the V-V line of the Figure 4 battery holder 20 is shown. Figure 6 A perspective view of the disassembled state with the circuit board 40 removed from the Figure 3 battery holder 20 is shown. Figure 7 A perspective view showing the Figure 6 disassembled battery holder 20 is shown. Figure 8 A perspective view of the lead board is shown. Figure 9 A perspective view of the Figure 2 battery pack 100 taken along the IX-IX line is shown. The battery pack 100 shown in these figures includes one or more secondary battery cells 1, a battery holder 20 that holds these one or more secondary battery cells 1, a circuit board 40 assembled to the battery holder 20, and an outer housing 10 that houses the battery holder 20 and the circuit board 40.

[0049] (Outer housing 10)

[0050] As shown in Figure 1 and Figure 2 , the outer housing 10 is a box-shaped housing with a hollow interior accommodation space. The accommodation space is formed in a shape and size capable of accommodating the battery holder 20 with the circuit board 40. In addition, the appearance of the outer housing 10 is formed in a shape corresponding to the accommodation space. In the example of Figure 1 , it is formed in a rectangular parallelepiped shape extending in one direction. In addition, the outer housing 10 is divided into upper and lower parts. Here, it is divided into an upper housing 11 and a lower housing 12. Further, a handle 13 is provided on the upper part of the outer housing 10. Such an outer housing 10 can be made of a material with excellent insulation properties, such as thermoplastic resins such as m-PPE (modified polyphenylene ether), ABS resin, PC (polycarbonate), PP (polypropylene), PBT (polybutylene terephthalate), silicone resin, unsaturated phenolic resin, unsaturated polyester, etc., and thermosetting resins.

[0051] (Battery holder 20)

[0052] The battery holder 20 housed in the outer housing 10 holds one or more secondary battery cells 1. In addition, as shown in Figures 3 to 6 , the circuit board 40 is assembled to one surface of the battery holder 20. As shown inFigure 3 , Figure 4 As shown in Figure 3 and Figure 4 , the battery holder 20 has a generally rectangular parallelepiped shape, and a circuit board 40 is assembled on its upper surface. On the upper surface of the outer casing 10, a slot 28 for inserting the circuit board 40 is formed. As shown in Figure 6 , the circuit board 40 is inserted into the slot 28 from the horizontal direction for assembly. In addition, the circuit board 40 inserted into the slot 28 is fixed by screwing. Figure 6 As shown in Figure 6 , the circuit board 40 is inserted into the slot 28 from the horizontal direction for assembly. In addition, the circuit board 40 inserted into the slot 28 is fixed by screwing.

[0053] (Battery accommodation part 21)

[0054] The battery holder 20 includes a battery accommodation part 21 for accommodating one or more secondary battery cells 1. Figure 7 As shown in Figure 7 , the battery holder 20 is divided into two parts left and right, and a battery accommodation part 21 for holding the secondary battery cell 1 is formed between the divided casings 22A and 22B. Such a battery holder 20 can be made of a material with excellent insulation properties, such as thermoplastic resins such as m-PPE (modified polyphenylene ether), ABS resin, PC (polycarbonate), PP (polypropylene), PBT (polybutylene terephthalate), silicone resin, unsaturated phenolic resin, unsaturated polyester and other thermosetting resins.

[0055] Each secondary battery cell 1 accommodated in the battery holder 20 has a cylindrical shape, and multiple thereof are stacked in a horizontally arranged state to form a battery assembly 2. On each assembly side surface 3 of the battery assembly 2, the end faces of the secondary battery cells 1 are respectively exposed in the same plane. The secondary battery cells 1 adjacent to each other in the vertical direction are offset and arranged in a manner that the circles of the end faces are eccentric. In addition, lead plates 30 are respectively arranged on both sides of the battery holder 20. Each lead plate 30 is fixed to the end faces of a plurality of secondary battery cells 1, and these secondary battery cells 1 are connected in series and in parallel. In the examples of Figure 5 and Figure 7 , 21 secondary battery cells 1 are connected in 7 series and 3 parallel. In addition, the number of secondary battery cells, the number of series and parallel connections can be appropriately changed according to specifications such as the voltage and capacity required for the battery pack. In addition, the posture of holding the secondary battery cell 1 by the battery holder 20 is not limited to the examples of Figure 5 etc., and any method can be used. For example, in the example of Figure 7 , the battery holder 20 holds a plurality of secondary battery cells 1 in a horizontal posture, but it is not limited thereto, and it can also be held in a vertical posture. In addition, on the side surface of the battery holder 20, the positive and negative surfaces of the secondary battery cell 1 are arranged in a mixed manner, but it is not limited thereto, and only the positive electrode or only the negative electrode can be uniformly arranged on the same surface. Figure 5 , Figure 7 In the examples of Figure 5 and Figure 7 , 21 secondary battery cells 1 are connected in 7 series and 3 parallel. In addition, the number of secondary battery cells, the number of series and parallel connections can be appropriately changed according to specifications such as the voltage and capacity required for the battery pack. In addition, the posture of holding the secondary battery cell 1 by the battery holder 20 is not limited to the examples of Figure 5 etc., and any method can be used. For example, in the example of Figure 7 , the battery holder 20 holds a plurality of secondary battery cells 1 in a horizontal posture, but it is not limited thereto, and it can also be held in a vertical posture. In addition, on the side surface of the battery holder 20, the positive and negative surfaces of the secondary battery cell 1 are arranged in a mixed manner, but it is not limited thereto, and only the positive electrode or only the negative electrode can be uniformly arranged on the same surface. Figure 7 etc., and any method can be used. For example, in the example of Figure 7 , the battery holder 20 holds a plurality of secondary battery cells 1 in a horizontal posture, but it is not limited thereto, and it can also be held in a vertical posture. In addition, on the side surface of the battery holder 20, the positive and negative surfaces of the secondary battery cell 1 are arranged in a mixed manner, but it is not limited thereto, and only the positive electrode or only the negative electrode can be uniformly arranged on the same surface. Figure 7 In the example of Figure 7 , the battery holder 20 holds a plurality of secondary battery cells 1 in a horizontal posture, but it is not limited thereto, and it can also be held in a vertical posture. In addition, on the side surface of the battery holder 20, the positive and negative surfaces of the secondary battery cell 1 are arranged in a mixed manner, but it is not limited thereto, and only the positive electrode or only the negative electrode can be uniformly arranged on the same surface.

[0056] (Secondary battery cell 1)

[0057] Each secondary battery cell 1 has positive and negative electrodes. The positive and negative electrodes are preferably provided on one end face of the secondary battery cell 1. For such a secondary battery cell 1, known secondary batteries such as lithium-ion secondary batteries, nickel-metal hydride batteries, and nickel-cadmium batteries can be appropriately used.

[0058] (Lead plate 30)

[0059] On the side surface of the battery holding member 20, a lead plate 30 is arranged. The lead plate 30 connects the electrodes on the end face of the secondary battery cell 1 to each other, and connects the secondary battery cells 1 in series and in parallel. These lead plates 30 are composed of metal plates with excellent conductivity such as nickel plates, aluminum, and iron. In addition, an insulating plate can be arranged on the end face of the lead plate 30 as needed. The insulating plate is composed of materials with excellent insulation such as paper and mica.

[0060] As Figure 8 shown, each lead plate 30 has a covering surface 31 and a bent piece 32. The covering surface 31 partially covers a pair of aggregate side surfaces 3 of the battery aggregate 2. The bent piece 32 is bent from the covering surface 31 at the upper end of the covering surface 31. Each bent piece 32 is respectively connected to the electrical connection region 42 of the circuit board 40. In a state where the bent pieces 32 of the lead plate 30 are bent in advance, the circuit board 40 is inserted into the slot 28, and each bent piece 32 is fixed to the electrical connection region 42, whereby the electrical connection between the lead plate 30 and the circuit board 40 can be easily performed.

[0061] The connection between the bent piece 32 of the lead plate 30 and the circuit board 40 is welding, fusion welding, bonding, etc., and known connection methods can be appropriately used according to the required strength, the material of the connection object, etc. Laser welding and ultrasonic fusion welding are preferably used.

[0062] (Circuit board 40)

[0063] The circuit board 40 is rectangular with a pair of end edges and a pair of side surfaces intersecting with the pair of end edges. The circuit board 40 is electrically connected to the secondary battery cell 1. A protection circuit and a charge and discharge circuit of the secondary battery cell 1 are installed in the circuit board 40. In addition, electronic components 50 such as an LED 50A and a switch 50B are installed in the circuit board 40. The electronic components 50 installed in the circuit board 40 are components that can be visually recognized or operated by the user from the outside of the outer housing 10. For example, the LED 50A can be visually recognized by the user from the outside of the outer housing 10, and the remaining capacity of the secondary battery cell 1 or the charge and discharge state can be indicated by the number of lit LED 50As. In addition, the switch 50B can be operated by the user from the surface of the outer housing 10, and is provided to indicate the display of the remaining capacity, etc. by the user pressing it. For such a circuit board 40, a hard resin such as a glass epoxy board can be suitably used.

[0064] (Electrical connection area 42)

[0065] The circuit board 40 has a plurality of electrical connection areas 42 for connecting to the plurality of lead plates 30, respectively. The electrical connection area 42 is a block-shaped area mounted on the circuit board 40. The bent piece 32 of the lead plate 30 is fixed to the electrical connection area 42 by resistance welding, laser welding, etc. Such a block-shaped electrical connection area 42 can be made of a material suitable for welding, such as a metal plated with aluminum nickel, iron nickel, etc., or nickel itself, a cladding plate, etc., depending on the material of the lead plate 30. Alternatively, a pad pattern formed on the surface of the circuit board can also be used as the electrical connection area.

[0066] The electrical connection region 42 includes an intermediate potential connection region 42A and a total potential connection region 42B. The intermediate potential connection region 42A is connected to any one of the plurality of lead plates 30 to detect the intermediate potential of the plurality of secondary battery cells 1. The total potential connection region 42B is connected to any other one of the plurality of lead plates 30 to detect the total potential of the plurality of secondary battery cells 1. Figure 6 In the example of FIG. 4 , the total potential connection region 42B is arranged at the corner of the circuit substrate 40 , and the intermediate potential connection regions 42A are arranged in the middle to be separated from each other.

[0067] (Slide-in construction)

[0068] The circuit substrate 40 is arranged on the upper surface of the battery receiving portion 21 of the battery holder 20. The battery holder 20 guides the circuit substrate 40 to the slot 28 and is provided with a fitting portion 24 that is pressed against at least one end edge of the circuit substrate 40. In this way, by inserting the circuit substrate 40 into the slot 28 and Figure 5 As shown in the cross-sectional view of FIG, the end edge of the circuit substrate 40 is pressed against the slide-in structure of the mounting portion 24, so that the circuit substrate 40 can be easily positioned in the battery holder 20. As a result, the work of electrically connecting the lead plate 30 and the circuit substrate 40 can be easily performed.

[0069] In a battery pack with multiple secondary battery cells, it is necessary to detect not only the total voltage of the electrical stack composed of the secondary battery cells, but also the intermediate potential. Therefore, the following process is performed: each lead plate is electrically connected to the circuit substrate to detect the potential of each part. Generally, the battery pack is provided with lead plates on the sides of the battery holder, the circuit substrate is fixed on the upper surface of the battery holder, and the side lead plates and the circuit substrate are connected by lead plates, lead pins, leads, etc. For example, in Figure 10In the battery pack 800 according to the comparative example shown, in order to measure the intermediate potential exhibited on the lead plate 830, the lead pin 833 is locked and connected to the upper surface of each lead plate 830. In this structure, it is necessary to manually perform the operation of locking the tip of the lead pin 833 to the lead plate 830, which takes time and effort.

[0070] In addition, in Figure 11 in the battery pack 900 according to another comparative example shown, in a state where the tip of the lead plate 930 is in an upright posture, the circuit board 940 is fixed to the upper surface of the battery holder 920 by screwing or the like. And, as Figure 12 shown, the tip of the lead plate 930 is manually bent so as to overlap the electrical connection region 942 provided on the circuit board 40, and is fixed by soldering or the like. This method also requires a process of manually bending the upper end of the lead plate 930, which also takes time and effort. Further, although not shown, there is also a structure in which the upper end of the lead plate is connected to the circuit board by a lead. However, similarly, it is necessary to solder the lead, the circuit board, and the lead plate. Not only does the man-hour increase, but also for the handling of the lead, the lead requires a certain length. Therefore, there is a problem that a mechanism for pressing the shaking of the lead is also required, and the structure becomes complicated.

[0071] In contrast, in the battery pack 100 according to the present embodiment, instead of placing the circuit board 40 on the upper surface of the battery holder 20, as shown in the exploded perspective view of Figure 6 , it is configured to be a sliding structure inserted into the slot 28 from the side. If it is this structure, since the lead plate 30 can be bent in advance as shown in the perspective view of Figure 13 , the following advantages are obtained: the process of manually bending the lead plate 30 can be omitted, and the man-hour can be reduced. In addition, by pressing the edge of the circuit board 40 against the fitting portion 24, relative positioning of the circuit board 40 and the battery holder 20 is achieved, and thus alignment of the bent piece 32 of each lead plate 30 and the electrical connection region 42 of the circuit board 40 is also achieved, and connection operations such as soldering become easy. That is, by fixing the circuit board 40 to the battery holder 20, it is possible to configure to perform positioning at the same time.

[0072] Further, if this structure is adopted, the advantage of being able to easily specify the connection order of the electrical connection regions 42 can also be obtained. In the structure for measuring the intermediate potential, the withstand voltage of the terminals for detecting the intermediate potential in the protection circuit or the like mounted on the circuit board 40 is designed according to the assumed potential. However, during assembly, depending on the connection state with other electrical connection regions 42, a situation may occur where a voltage higher than the assumed voltage is applied. To avoid this situation, it is necessary to connect in sequence from the ground side, i.e., the low-voltage side of the total potential connection region 42B, from the low voltage to the high voltage among the intermediate potential connection regions 42A, and finally connect to the total voltage, i.e., the high-voltage side of the total potential connection region 42B. In the battery pack 100 according to the present embodiment, the specification of such a connection order can be achieved by simply abutting and welding the bent pieces 32 of the lead plate 30 in a given order using a jig, and the advantage of being able to easily control the connection order can also be obtained. In addition, the jig mentioned here is used in the sense of also including connection tools. For example, it is also possible to adopt either a structure in which a welding rod for resistance welding as an additional component is abutted while pressing the bent piece using a pressing rod or the like as a jig, or a structure in which the bent piece is directly pressed by the welding rod itself while welding. In this specification, the equipment used in these connection processes is collectively referred to as a jig.

[0073] Furthermore, through the sliding-in structure, electronic components 50 such as the LED 50A and the switch 50B can be easily directly mounted on the circuit board 40 while being positioned. Especially in the battery pack 100 according to Embodiment 1, as Figure 5 , Figure 7 etc. show, without using sub-holders such as an LED holder and a fitting holder, electronic components 50 such as the LED 50A and the switch 50B that require visual recognition and operation from the outside of the outer housing 10 are directly mounted on the circuit board 40. In addition, by assembling the circuit board 40 on which such electronic components 50 are mounted into the battery holder 20 in a sliding-in structure, it is fixed in a positioned posture. Therefore, only the positioning of the battery holder 20 and the outer housing 10 needs to be performed, and the positioning operation can be made labor-saving. In addition, by not using sub-holders, the installation process of the electronic components 50 onto the sub-holders and the installation process of the sub-holders onto the circuit board 40 can be omitted. Along with the reduction of the component cost of the sub-holders, the manufacturing cost is also reduced.

[0074] (Guide wall 23)

[0075] The slot 28 that realizes the sliding-in structure is formed by a pair of guide walls 23 on the upper surface of the battery holder 20, and the guide walls 23 guide the two side surfaces of the circuit board 40 that intersect with one end edge. In Figure 6In the example shown, the guiding wall 23 is provided with a guiding L portion 23b for guiding both sides of the circuit board 40 on the upper surface of the battery housing portion 21. The guiding L portion 23b is bent in an L shape from the side surface of the battery holder 20 toward the inside. In this way, by guiding both side edges of the circuit board 40 with a pair of guiding walls 23, the circuit board 40 can be guided along the slot 28. In addition, in a state where the circuit board 40 is assembled to the upper surface of the battery housing portion 21 through the assembling portion 24, the other edge of the circuit board 40 opposite to one edge is in an exposed state.

[0076] The guiding wall 23 is integrally formed with the battery holder 20. However, it may be configured such that the guiding wall is formed of a member different from the battery holder, and the guiding wall is fixed to the upper surface of the battery holder.

[0077] (Lead window 23c)

[0078] In addition, as Figure 13 shown, a lead window 23c through which the bent piece 32 is exposed is opened in the guiding L portion 23b. With this structure, in a state where the circuit board 40 is inserted into the slot 28, the bent piece 32 of the lead board 30 is exposed from the lead window 23c, so that fixing operations such as soldering can be performed in the electrical connection region 42.

[0079] (Bent piece 32)

[0080] The bent piece 32 of each lead board 30 is preferably bent elastically from the covering surface 31. Thus, after the circuit board 40 is inserted into the slot 28 as shown in the cross-sectional view of Figure 14 , as shown in the cross-sectional view of Figure 15 , the bent piece 32 is pressed against the electrical connection region 42 from the upper surface with a jig JG or the like, and soldering and welding can be performed in a state of being in contact without a gap due to elastic deformation.

[0081] The bending angle θ is designed so that when the circuit board 40 is inserted into the slot 28, the bent pieces 32 of the respective lead boards 30 do not hinder the intrusion of the circuit board 40 into the slit. The bending angle θ of the bent piece 32 is set to 90° or less with respect to the covering surface 31, and is preferably set to 70° to 90° in consideration of manufacturing tolerances and the like. Thereby, in a state where the circuit board 40 is inserted along the guiding wall 23 and assembled to the battery holder 20, the lead board 30 can be easily pressed against the electrical connection region 42 of the circuit board 40. In addition, the smaller the bending angle θ is, the larger the amount of travel for pressing the bent piece 32 toward the electrical connection region 42 is. For this reason, in order to reduce the amount of travel for bending the bent piece 32 during soldering, the bending angle θ is not set to be too small, and more preferably set to about 80°.

[0082] [Embodiment 2]

[0083] On the other hand, the bending angle θ of the bending piece 32 may be set to 90° or more. This can save labor or eliminate the need for crimping with a clamp when welding the bending piece 32. Figures 16 to 17 Such an example is described with reference to the battery pack 200 according to the second embodiment shown in FIG. Figure 16 1 is a cross-sectional view of a battery pack 200 according to Embodiment 2. Figure 17 It shows that Figure 16 2 is a longitudinal sectional view of a state where a circuit substrate 240 of a battery pack 200 is inserted into a slot 228 of a battery holder 220. In these figures, the same reference numerals are given to the same components as those in the first embodiment, and detailed descriptions thereof are omitted as appropriate. In the battery pack 200 according to the second embodiment, Figure 16 As shown in FIG. 2 , the bending angle θ′ of the bending piece 232 is set to be greater than 90°. As a result, it is considered that when the circuit substrate 240 is inserted into the slot 228, the bending piece 232 will interfere with and hinder the insertion of the circuit substrate 240. Figure 17 As shown in FIG. 2 , the end edge of the circuit substrate 240 is formed into an inclined surface 240a that is inclined from the upper surface toward the lower surface. As a result, when the circuit substrate 240 is inserted into the slot 228, the bent piece 232 that contacts the inclined surface 240a at the front end is elastically deformed to be lifted from below, and even if it is bent by more than 90°, it will not hinder the circuit substrate 240 from entering the slot 228. As a result, the circuit substrate 240 can be inserted into the slot 228, and after insertion, the bent piece 232 is in contact with the electrical connection area 242, so that the welding and welding operations can also reduce the amount of crimping by the clamp, or omit the crimping itself.

[0084] In addition, if Figure 18 As in the battery pack 300 involved in the illustrated variation, by chamfering the end surface of the circuit substrate 340 into a curved shape from the upper surface to the lower surface, the end surface of the circuit substrate 340 can be easily inserted into the lower surface of the bent piece 332 and pushed up from below.

[0085] (Assembly section 24)

[0086] In addition, a mounting portion 24 is provided on the back side of the upper surface of the battery holder 20. The mounting portion 24 is mounted to at least one edge of the circuit board 40. Figures 5 to 6In the example, the positioning in the longitudinal direction of the circuit board 40 is performed by pressing the right end edge of the circuit board 40 into the fitting portion 24 and bringing it into contact with the fitting portion 24. Further, in the width direction of the circuit board 40, positioning is performed by a pair of guide walls 23, whereby positioning on the XY plane is performed. In a state where the circuit board 40 is positioned relative to the battery holder 20, as Figure 6 shown, the battery holder 20 and the circuit board 40 are screwed and fixed with screws.

[0087] As Figure 5 shown in the enlarged cross-sectional view of the main part, the fitting portion 24 is formed in a eaves shape so as to cover a part of the upper surface from the end edge of the circuit board 40 in a state where the circuit board 40 is placed on the upper surface of the battery housing portion 21. With this configuration, the circuit board 40 can be held by clamping the end edge with the eaves-shaped fitting portion 24. Further, the fitting portion 24 can be formed integrally with the battery housing portion 21.

[0088] (Cooperating portion 26)

[0089] Furthermore, the battery holder 20 includes a cooperating portion 26 that causes the electronic component 50 to cooperate with the outer housing 10 in a state where the circuit board 40 is assembled to the fitting portion 24. As described above, by accurately positioning the circuit board 40 and the battery holder 20, these electronic components 50 directly mounted on the circuit board 40 can cooperate with the outer housing 10 without using sub-holders such as an LED holder and a fitting holder for holding the electronic component 50. In other words, conventionally, operations of mounting the sub-holder on the circuit board 40 and mounting the circuit board 40 on the battery holder 20 were required, but in the battery pack 100 according to the first embodiment, only by the operation of mounting the circuit board 40 on the battery holder 20, the cooperation between the electronic component 50 and the outer housing 10 is achieved by the cooperating portion 26 incorporated in the battery holder 20.

[0090] (Holder opening window 26A)

[0091] Such a cooperating portion 26 can be formed in a part of the connecting portion. For example, when the electronic component 50 is a plurality of LEDs 50A, a plurality of separately opened holder opening windows 26A can be used as the cooperating portion 26 so that in a state where the circuit board 40 is assembled to the fitting portion 24, the plurality of LEDs 50A are individually exposed from the battery holder 20. As Figure 5 shown, a holder opening window 26A is opened in the protruding portion 25 protruding in a eaves shape in the connecting portion constituting the battery holder 20. As Figure 9As shown, the retainer opening windows 26A are opened at positions corresponding to the respective LEDs 50A mounted on the circuit substrate 40, in accordance with the number of LEDs 50A as the electronic components 50. In this way, by forming the retainer opening windows 26A individually for each LED 50A, the plurality of LEDs 50A can be well separated from each other. In addition, in order to improve the separation, the extension 25 formed with the retainer opening windows 26A may be set to black or the like so as to have light absorption properties for absorbing light. Furthermore, the inner surface of each opening window is set to an inclined surface 27, so that the light emitted by each LED 50A is easily reflected and taken out to the outside. In addition, a reflective film for reflecting light may be coated on the inclined surface 27 to improve the light extraction efficiency.

[0092] On the other hand, Figure 9 As shown in FIG. 1 and FIG. 2 , the outer case 10 that accommodates the battery holder 20 has case opening windows 14 opened at positions corresponding to the holder opening windows 26A. Thus, the user can visually check that the LEDs 50A are turned on even from the outside of the outer case 10 .

[0093] (Holder operating portion 26B)

[0094] In addition, the electronic component 50 is not limited to the LED 50A, and other components can also be used. Figure 9 In the example of , as a battery component, a switch 50B is provided in addition to the plurality of LEDs 50A. In this case, the cooperation portion 26 is a holder operating portion 26B provided at a position corresponding to the switch 50B when the circuit substrate 40 is mounted on the mounting portion 24. The holder operating portion 26B can be operated in conjunction with the switch 50B. For example, when the switch 50B is set as a push button, when the holder operating portion 26B is pressed from the upper surface, the back side thereof contacts the switch 50B, thereby being able to operate it.

[0095] Furthermore, in the outer casing 10, a casing operating portion 15 is provided at a position corresponding to the holder operating portion 26B, and the casing operating portion 15 can be operated in conjunction with the holder operating portion 26B. Thus, when the user operates the casing operating portion 15 of the outer casing 10, the back surface of the casing operating portion 15 contacts the holder operating portion 26B, and the holder operating portion 26B operates the switch 50B. In this way, the user can operate the switch 50B from the outside of the outer casing 10 via the holder operating portion 26B.

[0096] The housing opening window 14 and the housing operation portion 15 of the outer housing 10 are preferably arranged adjacent to each other. Figure 2In the example shown, an operation area 16 provided on the upper side of the surface of the exterior housing 10 is configured adjacent to the housing opening window 14 and the housing operation part 15. In addition, a sealing part 17 is attached to the operation area 16. The housing opening window 14 can be visually recognized from the outside through the sealing part 17. For example, it is possible to confirm from the outside through the sealing part 17 the light emission of the LED arranged in the holding member opening window 26A. In addition, the housing operation part 15 is also configured to be operable from above the sealing part 17. For example, for the switch 50B provided on the back side of the housing operation part 15, the switch 50B can be operated by pressing the housing operation part 15 from above the sealing part 17.

[0097] In addition, in a structure in which such a sealing part 17 is attached to the operation area 16, a notch or a cutout can also be provided on the sealing part 17 side. For example, a cutout can be provided in the sealing part 17 to expose the housing opening window 14 and the housing operation part 15 from the sealing part 17. In addition, a notch can also be formed on the contour corresponding to the housing operation part 15 to make it easier for the sealing part 17 to follow the movement such as the pressing-in and resetting of the housing operation part 15. Or, in Figure 2 the example, a plurality of holding member opening windows 26A of the battery holding member 20 are provided, and correspondingly, a plurality of housing opening windows 14 of the exterior housing 10 are also provided. However, it is also possible to make one housing opening window 14 open larger and make a plurality of holding member opening windows 26A open concentratedly, and at the same time, a plurality of sealing opening windows are opened on the sealing part 17 side corresponding to the holding member opening windows 26A.

[0098] In Figure 7 the example, the divided holding members 22A and 22B constituting the battery holding member 20 are made asymmetric. A holding member opening window 26A is provided in the divided holding member 22A, and a holding member operation part 26B is provided in the divided holding member 22B. However, the configuration of the cooperation part is not limited to this structure, and any layout such as providing a holding member opening window and a holding member operation part in one divided holding member can be appropriately adopted.

[0099] (Method for manufacturing a battery pack)

[0100] The manufacturing method of the above battery pack 100 includes: a step of fixing the covering surfaces 31 of a plurality of lead plates 30 on a pair of aggregate side surfaces 3 of the battery aggregate 2 where the end faces of the respective secondary battery cells 1 are exposed in the same planar shape, and the battery aggregate 2 is formed in a state where a plurality of secondary battery cells 1 accommodated in the battery holder 20 are stacked; a step of inserting the circuit board 40 into a slot 28 formed on one surface of the battery holder 20 and freely slidably divided by guiding a pair of side surfaces of the circuit board 40 through guiding walls 23 respectively, and opposing the bent pieces 32 of the respective lead plates 30 to a plurality of electrical connection regions 42; and a step of connecting the respective bent pieces 32 to the respective battery connection regions. Thus, since the circuit board 40 can be inserted into the slot 28 in a state where the bent pieces 32 of the lead plates 30 are pre-bent, and the respective bent pieces 32 can be fixed to the electrical connection regions 42, the electrical connection between the lead plates 30 and the circuit board 40 can be easily performed. In addition, the step of inserting the circuit board 40 into the slot 28 and opposing the bent pieces 32 to a plurality of electrical connection regions 42 may also include the following steps: bringing the edge of the circuit board 40 into contact with an assembling portion 24 provided to intersect the pair of guiding walls 23, and positioning the relative position of the circuit board 40 and the battery holder 20 so that the electrical connection regions 42 and the bent pieces 32 are in overlapping positions with each other. Thus, the circuit board 40 and the battery holder 20 can be easily positioned so that the bent pieces 32 and the electrical connection regions 42 are in overlapping postures with each other. Further, it may be that in the step of inserting the circuit board 40 between the pair of guiding walls 23, the upper ends of the plurality of lead plates 30 are elastically bent at a position above the trajectory of inserting the circuit board 40 between the pair of guiding walls 23, and in the step of electrically connecting the plurality of electrical connection regions 42 and the lead plates 30 placed in an overlapping state, the upper ends of the respective lead plates 30 are crimped to the respective electrical connection regions 42 by a jig. Thus, the respective lead plates 30 and the circuit board 40 can be simply electrically connected.

[0101] In the above example, the battery pack is assembled to an electrical device to be driven, and power is supplied to the electrical device. In addition, when the remaining capacity of the battery pack is small and the battery pack has deteriorated over time, the battery pack can be replaced, and thus the electrical device can continue to be used. However, the present disclosure does not limit the battery pack to a replaceable type mainly containing secondary battery cells, and can also be applied to a type in which secondary battery cells are accommodated in the housing of the electrical device. In the present disclosure, a battery pack means that as long as secondary battery cells are accommodated in a housing, a structure in which drive secondary battery cells are built in the housing of the electrical device itself is also called a battery pack. That is, the present disclosure is not limited to a replaceable battery pack, and can also be applied to an electrical device with built-in secondary battery cells.

[0102] Industrial applicability

[0103] The battery pack and its manufacturing method according to the present disclosure can be suitably used as a driving power source for a power-assisted bicycle, an autonomous mobile robot for delivery, an electric cart for delivery or a golf course, an electric scooter, a construction machine, a hybrid vehicle, an electric vehicle, etc. In addition, it can also be appropriately used as a power source for portable electrical devices such as wireless communication devices, electric cleaners, and electric tools, as a backup power source for servers for stationary power storage applications, and as a power supply device for household, office, and factory uses, etc.

[0104] -Symbol Explanation-

[0105] 100…Battery pack

[0106] 1…Secondary battery cell

[0107] 2…Battery assembly

[0108] 3…Side of the assembly

[0109] 10…Outer housing

[0110] 11…Upper housing

[0111] 12…Lower housing

[0112] 13…Handle

[0113] 14…Housing opening window

[0114] 15…Housing operation part

[0115] 16…Operation area

[0116] 17…Sealing part

[0117] 20…Battery holder

[0118] 21…Battery accommodation part

[0119] 22A, 22B…Divided housing

[0120] 23…Guide wall; 23b…Guide L part; 23c…Lead wire window

[0121] 24…Assembly part

[0122] 25…Protrusion part

[0123] 26…Cooperating part; 26A…Holder opening window; 26B…Holder operation part

[0124] 27…Inclined surface

[0125] 28…Slot

[0126] 30…Lead wire board

[0127] 31…Covered surface

[0128] 32…Bending piece

[0129] 40…Circuit board

[0130] 42…Electrical connection area; 42A…Intermediate potential connection area; 42B…Total potential connection area

[0131] 50…Electronic component; 50A…LED; 50B…Switch

[0132] 200…Battery pack

[0133] 220…Circuit board

[0134] 228…Slot

[0135] 232…Bending piece

[0136] 240…Circuit board; 240a…Inclined surface

[0137] 242…Electrical connection area

[0138] 300…Battery pack

[0139] 332…Bending piece

[0140] 340…Circuit board

[0141] 800…Battery pack

[0142] 830…Lead board

[0143] 833…Lead pin

[0144] 900…Battery pack

[0145] 920…Battery holder

[0146] 930…Lead board

[0147] 942…Electrical connection area

[0148] JG…Fixture

[0149] θ, θ’…Bending angle.

Claims

1. A battery pack, comprising: a plurality of secondary battery cells; a plurality of lead plates for connecting the plurality of secondary battery cells in series and / or in parallel; a battery holder for holding the plurality of secondary battery cells and the plurality of lead plates; a circuit board, which is rectangular with a pair of end edges and a pair of side surfaces intersecting the pair of end edges, and has a plurality of electrical connection regions for respectively connecting to the plurality of lead plates; and a pair of guide walls, which form a slot on one surface of the battery holder for inserting the circuit board, and the slot guides the pair of side surfaces of the circuit board respectively; the plurality of lead plates have bent pieces, and the bent pieces are respectively connected to the electrical connection regions of the circuit board in a bent form; in a state where the circuit board is inserted into the slot, the bent pieces are respectively connected to the plurality of electrical connection regions, and the plurality of lead plates are electrically connected to the circuit board.

2. The battery pack according to claim 1, wherein the plurality of secondary battery cells are cylindrical with different electrodes on a pair of end faces; the plurality of lead plates respectively have a covering surface, and the covering surface partially covers a pair of aggregate side surfaces of a battery aggregate formed by laminating the plurality of secondary battery cells, where the end faces of the respective secondary battery cells are exposed in the same planar shape; the bent pieces project from the covering surface in a bent manner; the bent pieces are connected to the electrical connection regions of the circuit board.

3. The battery pack according to claim 2, wherein the battery holder has a battery accommodation portion for accommodating the plurality of secondary battery cells; the circuit board is assembled on the upper surface of the battery accommodation portion.

4. The battery pack according to claim 2, wherein the guide walls are integrally formed with the battery holder.

5. The battery pack according to claim 2, wherein the guide walls have guide L portions, and the guide L portions are formed in an L shape so as to cover from a pair of side surfaces to the upper surface of the circuit board; in the guide L portions, lead windows for exposing the bent pieces are opened.

6. The battery pack according to claim 3, wherein the battery pack further comprises: an assembly portion for covering the other end edge of the circuit board in a state where the circuit board is inserted into the slot.

7. The battery pack according to claim 6, wherein the assembly portion is formed in a eaves shape protruding from the upper surface of the battery accommodation portion; the battery pack is configured such that in a state where the circuit board is inserted into the slot, from the other end edge of the circuit board to a part of the upper surface, the circuit board is covered by the eaves-shaped assembly portion.

8. The battery pack according to any one of claims 2 to 7, wherein the bent pieces of the respective lead plates are elastically bent from the covering surface.

9. The battery pack according to claim 8, wherein the angle at which the bent pieces of the respective lead plates are bent with respect to the covering surface is 70° to 90°.

10. The battery pack according to claim 1, wherein the plurality of electrical connection regions include: An intermediate potential connection region is connected to any one of the plurality of lead plates to detect the intermediate potential of the plurality of secondary battery cells; and A total potential connection region is connected to any other one of the plurality of lead plates to detect the total potential of the plurality of secondary battery cells.

11. A method for manufacturing a battery pack, the battery pack comprising: A plurality of secondary battery cells; Lead plates, which are a plurality of lead plates that connect the plurality of secondary battery cells in series and / or in parallel, and are formed by bending bending pieces in advance; A battery holder that holds the plurality of secondary battery cells and the plurality of lead plates; and A circuit board, which is rectangular with a pair of end edges and a pair of side surfaces intersecting with the pair of end edges, and has a plurality of electrical connection regions for respectively connecting to the plurality of lead plates, The method for manufacturing the battery pack includes: A step of fixing the coated surfaces of the plurality of lead plates on a pair of aggregate side surfaces of the battery aggregate where the end faces of the respective secondary battery cells are exposed in the same plane, and the battery aggregate is formed in a state where the plurality of secondary battery cells accommodated in the battery holder are stacked; A step of inserting the circuit board into a slot formed in one surface of the battery holder and defined by a pair of guide walls that guide the pair of side surfaces of the circuit board to slide freely, and making the bending pieces of the respective lead plates face the plurality of electrical connection regions; and A step of connecting each bending piece to each battery connection region.

12. The method for manufacturing a battery pack according to claim 11, wherein The step of inserting the circuit board into the slot and making the bending pieces face the plurality of electrical connection regions includes the following steps: Making the end edge of the circuit board abut against an assembly portion provided to intersect the pair of guide walls, and positioning the relative position of the circuit board and the battery holder so that the electrical connection regions and the bending pieces are in overlapping positions.

13. The method for manufacturing a battery pack according to claim 12, wherein In the step of inserting the circuit board between the pair of guide walls, the upper ends of the plurality of lead plates are elastically bent at a position above the trajectory of inserting the circuit board between the pair of guide walls, In the step of electrically connecting the plurality of electrical connection regions and the lead plates in the overlapping state, the upper ends of the respective lead plates are pressed against the respective electrical connection regions by a jig.

14. The method for manufacturing a battery pack according to any one of claims 11 to 13, wherein The bending pieces of the respective lead plates are bent relative to the coated surface by 70° to 90°.

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