Electric power supply device, lead plate provided with fuse link function, and method for manufacturing same

Abstract

This electric power supply device comprises a plurality of secondary battery cells, and a lead plate that electrically connects the plurality of secondary battery cells. The lead plate has a fuse link portion that blocks electrification by being melted in response to an overcurrent. Part of the fuse link portion is provided with a fusion region that is more readily fused in response to an overcurrent than other regions. In the lead plate, at least part of the fuse link portion is coated with a coating material. The thickness of the fusion region is made less than that of the other regions of the fuse link portion.

Description

Power supply device, lead plate with fuse link function and manufacturing method thereof

[0001] The present disclosure relates to a power supply device and a lead plate having a fuse link function, and a method for manufacturing the same.

[0002] Power supply devices are used in applications where multiple rechargeable secondary battery cells such as lithium-ion secondary batteries are connected in series or parallel and housed in an exterior case to drive electrical equipment such as power tools, or to drive electrically-driven mobile objects such as vehicles and construction machinery, or for stationary power storage or backup purposes (see, for example, Patent Document 1). The secondary battery cells used in such power supply devices are electrically connected by metal plates called lead plates or bus bars (hereinafter referred to as "lead plates" in this disclosure).

[0003] Some such lead plates, such as lead plate 830 shown in Figure 10, have a fuse link 833 that acts as a current fuse, cutting off the current by intentionally melting a portion in response to an overcurrent.

[0004] However, with conventional lead plates, it has not been possible to identify or control which portion will melt when the fuse link operates. To address this issue, it is conceivable to form a fuse link 933 with a narrower width in part, as in the lead plate 930 shown in Figure 11 , and mechanically provide an area 934 that is more likely to melt. However, this configuration has the problem of weakening the mechanical strength of the narrower area that constitutes the fuse link 933, reducing reliability.

[0005] JP 2016-066455 A

[0006] One object of one embodiment of the present disclosure is to provide a power supply device capable of regulating the melting position of a fuse link, a lead plate having a fuse link function, and a method for manufacturing the same. Another object of another embodiment is to provide a power supply device capable of suppressing a decrease in the mechanical strength of the fuse link, a lead plate having a fuse link function, and a method for manufacturing the same. Note that the description of these objects and problems of the present disclosure does not preclude the existence of other objects and problems. Furthermore, it is not necessary for one embodiment of the present disclosure to solve all of these problems. Furthermore, problems other than these may be extracted from the description of the specification, drawings, and claims of the present disclosure.

[0007] A power supply device according to one embodiment of the present disclosure comprises a plurality of secondary battery cells and a lead plate electrically connecting the plurality of secondary battery cells, the lead plate having a fuse link portion that cuts off current by melting in response to an overcurrent, the fuse link portion having a fusing region in a portion thereof that is more likely to melt in response to an overcurrent than other regions, the lead plate having at least a portion of the fuse link portion coated with a coating material, and the thickness of the fusing region is thinner than the thickness of the other regions of the fuse link portion.

[0008] Another embodiment of the power supply device includes a plurality of secondary battery cells and a lead plate electrically connecting the plurality of secondary battery cells, the lead plate having a fuse link portion that cuts off current by melting in response to an overcurrent, the fuse link portion having a fusing region in part that is more likely to melt in response to an overcurrent than other regions, the lead plate having an area other than the fusing region coated with a first coating material and the fusing region coated with a second coating material, the first specific heat of the first coating material being higher than the second specific heat of the second coating material.

[0009] Furthermore, a lead plate with a fuse link function in another form is a lead plate for electrically connecting secondary battery cells, and is provided with a fuse link portion that cuts off the flow of electricity by melting in response to an overcurrent, and the fuse link portion has a fusing area in part that is more likely to melt in response to an overcurrent than other areas, and the lead plate has at least a portion of the fuse link portion coated with a coating material, and the thickness of the fusing area is thinner than the other areas of the fuse link portion.

[0010] Furthermore, another embodiment of a method for manufacturing a power supply device includes a plurality of secondary battery cells and a lead plate that electrically connects the plurality of secondary battery cells and has a fuse link portion that cuts off current by melting in response to an overcurrent, the method including the steps of: coating at least a portion of the fuse link portion of the lead plate with a coating material, and forming, within the fuse link portion, a coated area that is coated with the coating material and an uncoated area that is not coated with the coating material; and connecting the lead plate to the plurality of secondary battery cells.

[0011] Furthermore, another embodiment of a method for manufacturing a lead plate is a method for manufacturing a lead plate for electrically connecting secondary battery cells, and includes the steps of preparing the lead plate having a fuse link portion that cuts off current by melting in response to an overcurrent, and coating at least a portion of the fuse link portion of the lead plate with a coating material to form, within the fuse link portion, a covered area that is coated with the coating material and an uncovered area that is not coated with the coating material.

[0012] According to one embodiment of the power supply device and lead plate with fuse link function and the manufacturing method thereof disclosed herein, the thermal capacity is increased by applying a coating to the fuse link portion, and when an overcurrent is passed through the lead plate, the uncoated area of ​​the fuse link portion that is not coated melts first, thereby making it possible to define the melting portion.

[0013] In addition, in a power supply device according to another embodiment, by applying different coating materials to the fuse link portion in the fusing region where it is desired to fuse and in other regions, the heat capacity of the fusing region of the fuse link portion is made lower than that of the other regions of the fuse link portion, thereby hastening fuse-fusing and making it possible to control the fusing region.

[0014] 1 is a perspective view showing a power supply device according to embodiment 1. FIG. 2 is an exploded perspective view of the power supply device of FIG. 1. FIG. 3 is an exploded perspective view of the battery block of FIG. 2. FIG. 4 is an enlarged perspective view of the battery block of FIG. 2. FIG. 5 is an enlarged plan view showing a lead plate of the power supply device of FIG. 4. FIG. 6 is an enlarged perspective view of a main part of the fuse link portion of FIG. 5. FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. 6. FIG. 8 is an enlarged cross-sectional view showing a fuse link portion of a lead plate according to embodiment 2. FIG. 9 is an enlarged cross-sectional view showing a fuse link portion of a lead plate according to embodiment 3. FIG. 10 is a plan view showing a lead plate according to comparative example 1. FIG. 11 is a plan view showing a lead plate according to comparative example 2.

[0015] The embodiments of the present disclosure may be specified by the following configurations and features.

[0016] In a power supply device according to another aspect of the present disclosure, in any of the above aspects, the fusing region is not covered with the coating material. With this configuration, when an overcurrent flows through the lead plate, the uncovered portion is first to be blown out, thereby making it possible to define the fusing region.

[0017] Furthermore, in the power supply device according to another aspect of the present disclosure, in any one of the above aspects, the lead plates are entirely covered with the coating material except for the fusing region.

[0018] Furthermore, in the power supply device according to another aspect of the present disclosure, in any of the above aspects, the length of the fusion region is 10% to 70% of the length of the fuse link portion.

[0019] In a power supply device according to still another aspect of the present disclosure, in any of the above aspects, the coating material is a material that increases the heat capacity of the lead-plate. By coating the lead-plate with the coating material, the heat capacity is increased, making it difficult for the lead-plate to melt, thereby making it possible to differentiate the melting speed from the melting region.

[0020] In addition, in the power supply device according to another aspect of the present disclosure, in any of the above aspects, the coating material is made of an insulating material. With this configuration, the side of the lead plate that is coated with the coating material is insulated, thereby preventing unintended conduction and improving safety.

[0021] In a power supply device according to still another aspect of the present disclosure, in any of the above aspects, the coating material is black paint. By coating the lead plates with black paint, the emissivity is changed, making them less likely to melt, thereby making it possible to differentiate the melting speed from the melting region.

[0022] Embodiments of the present invention will be described below with reference to the drawings. However, the embodiments described below are merely examples for embodying the technical concept of the present invention, and the present invention is not limited to these. Furthermore, this specification in no way specifies the components set forth in the claims as components of the embodiments. The dimensions, materials, shapes, and relative positions of components described in the embodiments are not intended to limit the scope of the present invention, and are merely illustrative unless otherwise specified. The size and relative positions of components shown in the drawings may be exaggerated for clarity. Furthermore, in the following description, the same names and symbols indicate identical or similar components, and detailed descriptions will be omitted as appropriate. Furthermore, the elements constituting the present invention may be configured with the same components, so that one component serves multiple functions, or conversely, the function of one component may be shared by multiple components.

[0023] The power supply device of the present invention can be used as a driving power source for mobile objects such as electric carts, electric scooters, and assisted bicycles, as a power source for portable electrical equipment such as radios, electric cleaners, and power tools, as a backup power source for servers in stationary power storage applications, as a power supply device for home, office, and factory use, and as a driving power source for vehicles such as hybrid cars and electric automobiles. Below, as one embodiment of the present invention, a power supply device used as a driving power source for an electric cart will be described.

[0024] [Embodiment 1] A power supply device 100 according to Embodiment 1 of the present invention is shown in Figures 1 to 7. In these figures, Figure 1 is a perspective view showing the power supply device 100 according to Embodiment 1, Figure 2 is an exploded perspective view of the power supply device 100 of Figure 1, Figure 3 is an exploded perspective view of the battery block 2 of Figure 2, Figure 4 is an enlarged perspective view of the battery block 2 of Figure 2, Figure 5 is an enlarged plan view showing the lead plate 30 of the power supply device 100 of Figure 4, Figure 6 is an enlarged perspective view of a main portion of the fuse link portion 33 of Figure 5, and Figure 7 is a cross-sectional view taken along line VII-VII of Figure 6. The power supply device 100 shown in these figures includes an outer case 10, a battery block 2, and a circuit board 3.

[0025] (External Case 10) The external case 10 houses the battery block 2 and circuit board 3. Any shape that has an internal storage space can be used for the external shape of the external case 10. In the example shown in Figures 1 and 2, the external shape of the external case 10 is a box shape that extends in one direction.

[0026] As shown in Figure 2, the exterior case 10 is divided into an upper case 11 and a lower case 12. The exterior case 10 is preferably made of a material with excellent insulating properties, such as a resin such as polycarbonate or PC-ABS alloy. However, the exterior case may also be made of a metal material such as aluminum or its alloy. An internal space is provided inside the exterior case 10 to house the battery block 2 and circuit board 3.

[0027] (Battery Block 2) The battery block 2 is also called a core pack. The battery block may be composed of multiple sub-blocks. The battery block 2 is composed of multiple secondary battery cells 1. The multiple secondary battery cells 1 are connected in series or in parallel via lead plates 30. In the example shown in FIG. 3 , 90 secondary battery cells are connected in 9 series and 10 parallel configurations. The number of series connections or parallel connections of the secondary battery cells that make up the battery block 2 can be set as desired according to the required specifications.

[0028] The battery block 2 includes a battery holder 21 that houses multiple rechargeable battery cells 1. The battery holder 21 has multiple storage cylinders 22 that individually store the rechargeable battery cells 1. For example, each battery holder 21 can be divided into two sub-holders 21A and 21B, with the two storage cylinders 22 sandwiching the rechargeable battery cells 1 from above and below. Such battery holders 21 can be made of a resin with excellent insulating properties, such as polycarbonate. Note that in the example shown in Figure 3, the battery block 2 is composed of 90 rechargeable battery cells 1, but the number of rechargeable battery cells that make up the battery block is not limited to this and can be any number.

[0029] (Secondary battery cells 1) Each secondary battery cell 1 can be a secondary battery cell with a cylindrical or rectangular outer shape. In the example shown in Fig. 3 etc., cylindrical secondary battery cells 1 are used in a staggered arrangement in a vertical orientation. Note that the number and arrangement of the secondary battery cells 1 are not limited to this example, and any number and arrangement can be used as appropriate. For example, cylindrical secondary battery cells may be arranged in a matrix.

[0030] Each secondary battery cell 1 has a positive and negative electrode, preferably located on one end surface 1c of the secondary battery cell 1. Known secondary batteries such as lithium-ion secondary batteries, nickel-metal hydride batteries, and nickel-cadmium batteries can be used as the secondary battery cells 1 (lead plates 30).

[0031] Lead plates 30 are arranged on the side surfaces of the battery holder 21. As shown in FIG. 4 , the lead plates 30 connect the electrodes of the end surfaces 1c of the rechargeable battery cells 1 to each other, connecting the multiple rechargeable battery cells 1 in series or parallel. These lead plates 30 also connect the multiple battery cells 1 in parallel. The lead plates 30 have fixing pieces 32 protruding from multiple locations on a base portion 31 that forms the main surface of the lead plate 30, and are electrically connected to the end surfaces 1c of the rechargeable battery cells 1 by known methods such as spot welding, laser welding, resistance welding, and ultrasonic welding. These lead plates 30 are made of a metal plate with excellent conductivity, such as a nickel plate. The lead plates 30 also have fuse links 33 that melt in response to an overcurrent to interrupt current flow, as a path to each fixing piece 32 (details will be described later).

[0032] (Insulating Plates 4) Insulating plates 4 are also placed on the end faces of the lead plates 30. In the example shown in Figure 3, the insulating plates 4 are large enough to cover the entire surface of the lead plates 30 of the battery block 2. Electrode windows 41 are also partially opened to expose the electrode portions of the lead plates 30. These insulating plates 4 are made of a material with excellent insulating properties, such as paper or mica.

[0033] (Circuit Board 3) The battery block 2 is connected to the circuit board 3 via lead plates 30. The circuit board 3 is equipped with a charge / discharge circuit that charges and discharges the rechargeable battery cells 1, and a protection circuit that monitors the voltage and temperature of the rechargeable battery cells 1 and cuts off the current in the event of an abnormality. The circuit board 3 is made of a glass epoxy board or the like. A board holder for holding the circuit board 3 may also be provided.

[0034] (Fuse Link Portion 33) As shown in FIG. 4 , the lead plate 30 includes a base portion 31 constituting the main surface, fixing pieces 32 provided on the base portion 31 at multiple locations corresponding to the terminals of the secondary battery cells 1 for fixing the terminals to the secondary battery cells 1, and fuse link portions 33 connecting the base portion 31 and each fixing piece 32. The fuse link portions 33 are components that melt to interrupt current flow when an overcurrent flows through the lead plate 30. FIG. 5 shows an enlarged view of the lead plate 30 in FIG. 4 . As shown in this figure, the fuse link portion 33 extends in an arm-like shape from the base portion 31 to the fixing pieces 32. In the example shown in FIG. 5 , the fuse link portion 33 is formed in an arc shape to fit around the periphery of the end face 1 c of the cylindrical secondary battery cell 1. However, the shape of the fuse link portion is not limited to this shape and can be any shape that can melt in response to an overcurrent.

[0035] (Fusing Region 34) The fuse link portion 33 has a fusing region 34 that is more likely to melt in response to an overcurrent than other regions of the fuse link portion 33. By specifying the location within the fuse link portion 33 where the fuse will blow, it is possible to more safely interrupt the current when an overcurrent flows. For example, if the fuse link portion 33 is elongated and thin, and electronic components or the like are present nearby, an arc may be generated during the fuse blow, resulting in unintended current flow. Therefore, by specifying that the fuse will blow in a region free of electronic components or the like, unintended operation during the fuse blow can be avoided, thereby improving the safety of the power supply device 100.

[0036] In a conventional lead plate 830 provided with a fuse link 833 as shown in Figure 10, when an overcurrent is passed through the fuse link 833 and the fuse link 833 operates, it is not possible to predict which portion of the fuse link 833 will melt, and it is not possible to control the melting position to be confined within a specific location. To address this issue, a possible solution is to form the fuse link 933 in a narrower portion, as in the lead plate 930 shown in Figure 11, and mechanically provide an area 934 that is more likely to melt. However, this configuration has the problem of weakening the mechanical strength of the narrower area, reducing reliability. Furthermore, changing the shape of the fuse link 933 itself increases the cost of parts such as molds.

[0037] In contrast, in the power supply device 100 according to this embodiment, rather than changing the physical shape of the fuse link portion 33, as shown in Fig. 6 and other figures, a coating material 40 is applied to the fuse link portion 33, and the melting region is defined by the film thickness of the coating material 40. With this configuration, it is possible to use fuse link portions 33 of an existing shape while controlling the melting region 34 of the fuse link portion 33, as will be described in detail below.

[0038] (Coating Material 40) In the lead plate 30, at least a portion of the fuse link portion 33 is coated with a coating material 40, forming a non-fuse region 35, which is a covered region coated with the coating material 40, and a fuse region 34, which is an uncovered region not covered with the coating material 40, within the fuse link portion 33. As shown in FIG. 7 , the thickness d1 of the fuse region 34, which fuses in response to an overcurrent, is thinner than the thickness d2 of the region other than the fuse region 34, i.e., the non-fuse region 35. In other words, by coating the non-fuse region 35 other than the fuse region 34 of the fuse link portion 33 with the coating material 40, the overall film thickness of the lead plate 30 is increased. As a result, the heat capacity of the coated region of the fuse link portion 33 is increased, and when an overcurrent is passed through the lead plate 30, the thinner coated portion fuses first, thereby defining the fuse region. In particular, since the region to be fused can be defined while maintaining the original shape of the lead plate 30, the present invention has the advantage of being easy to apply at low cost.

[0039] Coating material 40 is made of a material that increases the heat capacity of lead plate 30. Coating lead plate 30 with such coating material 40 increases the heat capacity of the coated region of lead plate 30, making it more difficult to fuse, and creates a relative difference in the fuse speed between this region and fuse region 34, making it possible for fuse region 34 to fuse first.

[0040] Black paint can be used as the coating material 40. Black paint is inexpensive, and painting techniques are well established, making it extremely easy to introduce. Coating the lead plate 30 with black paint changes the emissivity, making it less likely to melt.

[0041] 6 and 7, the fusion region 34 is not coated with the coating material 40. With this configuration, the coating material 40 can be easily applied to only the non-fusion region 35, excluding the fusion region 34, in a manner similar to masking paint. As a result, by changing the emissivity of the coated region and increasing its heat capacity, a structure can be achieved in which the masked fusion region 34 is fused relatively earlier.

[0042] Furthermore, the coating material 40 may be applied only to the fuse link portion 33 of the lead plate 30, or may cover the entire surface of the lead plate 30 except for the fusion region 34. This allows only the fusion region 34 to be masked and the coating material 40, such as black paint, applied to the surface, making it easy to create a difference in film thickness between the fusion region 34 and the other regions.

[0043] An insulating material can also be used for the coating material 40. In particular, in a configuration in which the coating material 40 is applied to the entire lead plate 30, for example, as shown in Figure 6, the back side of the fixing piece 32 of the lead plate 30 is fixed to the terminal of the secondary battery cell 1 to establish electrical continuity, while the insulating coating material 40 is applied to the front side of the lead plate 30, thereby improving the insulation of the front side of the lead plate 30 and preventing unintended electrical continuity, thereby improving safety.

[0044] The fusing region 34 is preferably located in the middle of the fuse link portion 33. This allows the fuse to fuse stably in the fusing region 34, thereby cutting off the current flowing through the lead plate 30. However, the fusing region 34 can be set appropriately depending on the arrangement of the fuse link portion 33 in the battery module and the layout of other components such as nearby electronic components.

[0045] The length of the fusion region 34 is preferably 10% to 70% of the length of the fuse link portion 33. As described above, the region on the fuse link portion 33 that is to be fused can be arbitrarily designed depending on the surrounding members, the installation environment, and the like.

[0046] [Embodiment 2] In the above example, the coating material 40 is not applied to the fusion region 34, thereby hastening the melting of the region without the coating material 40, thereby allowing the region without the coating material 40 to function as the melting region 34. However, the present disclosure is not limited to this configuration. While the coating material 40 is also applied to the fusion region 34, the thickness of the coating material 40 in the fusion region 34 can be made thinner to create a difference in heat capacity between the fusion region 34 and the other regions, thereby facilitating melting. Such an example is shown in the cross-sectional view of Figure 8 as a power supply device according to embodiment 2. In this example, components similar to those in embodiment 1 and the like are designated by the same reference numerals, and detailed descriptions thereof will be omitted where appropriate.

[0047] 8, the fuse link portion 33 of the lead plate 30 is coated with the coating material 40 over the entire area, including the fusion region 34, with the thickness d1' of the fusion region 34 being thinner than the thickness d2' of the non-fusion region 35 outside the fusion region 34. As a result, the amount of coating material 40 in the fusion region 34 is smaller, so the heat capacity is lower than in the non-fusion region 35, and fusion is more accelerated than in the non-fusion region 35. Furthermore, with this configuration, the coating material 40 is also coated on the fusion region 34, so that additional functionality can be achieved by the coating material 40. For example, if an insulating material is applied as the coating material 40, insulation is also added to the fusion region 34, contributing to improved safety.

[0048] Third Embodiment In the above example, the same coating material 40 is used, and the thermal capacity is varied by changing the thickness of the coating material 40 to adjust the local melting speed of the fuse link portion 33. However, the present disclosure is not limited to this configuration, and the melting speed can also be adjusted by changing the material of the coating material 40. Such an example is shown in the cross-sectional view of Figure 9 as a power supply device according to a third embodiment. In this example, the same components as those in the first embodiment and the like are designated by the same reference numerals, and detailed description thereof will be omitted where appropriate.

[0049] The fuse link portion 33 of the lead plate 30 shown in FIG. 9 is coated with a coating material 40 over the entire area, including the fusion region 34. The melting speed is controlled by applying two coating materials with different specific heats, rather than by the thickness of the coating material. Specifically, a first coating material 41 having a first specific heat and a second coating material 42 having a second specific heat are used. The first specific heat of the first coating material 41 is higher than the second specific heat of the second coating material 42. The non-fuse region 35 outside the fusion region 34 is coated with the first coating material 41. Meanwhile, the fusion region 34 is coated with the second coating material 42. By applying different coating materials 40 to the fuse link portion 33 in the region to be melted and the other regions, the heat capacity of the fusion region 34 is lower than that of the other regions, accelerating melting and thereby enabling control of the fusion region 34.

[0050] 9, the thicknesses of non-fuse region 35 and fusion region 34 are both set to the same value, d3, but the thicknesses may be different as long as the heat capacity of fusion region 34 is sufficiently lower than the heat capacity of non-fuse region 35. Here, "sufficiently" refers to a difference that ensures that fusion region 34 melts faster than non-fuse region 35.

[0051] [Manufacturing Method of Power Supply Device] A method for manufacturing a power supply device in which multiple secondary battery cells 1 are electrically connected via lead plates 30 is described below. First, a lead plate 30 is prepared, which has a fuse link portion 33 that cuts off current by melting in response to an overcurrent. Next, at least a portion of the fuse link portion 33 of this lead plate 30 is coated with a coating material 40, thereby forming a covered region coated with the coating material 40 and an uncoated region within the fuse link portion 33 that is not coated with the coating material 40. This makes the thickness of the fusing region 34, which is more likely to melt in response to an overcurrent than other regions within the fuse link portion 33, thinner than the other regions of the fuse link portion 33. Next, this lead plate 30 is connected to multiple secondary battery cells 1. By coating the fuse link portion 33, the thermal capacity is increased, and when an overcurrent flows through the lead plate 30, the thinner coated portion melts first, thereby defining the fusing portion.

[0052] [Manufacturing Method of Lead Plate 30] A manufacturing method of the lead plate 30 for electrically connecting the secondary battery cells 1 is now described. First, a lead plate 30 is prepared, which has a fuse link portion 33 that cuts off current by melting in response to an overcurrent. Next, at least a portion of the fuse link portion 33 of this lead plate 30 is coated with a coating material 40, thereby forming a covered region coated with the coating material 40 and an uncovered region within the fuse link portion 33 that is not covered with the coating material 40. This makes the thickness of the fusing region 34, which is more likely to melt in response to an overcurrent than other regions within the fuse link portion 33, thinner than the other regions of the fuse link portion 33. Coating the fuse link portion 33 increases its heat capacity, and when an overcurrent flows through the lead plate 30, the thinner coated portion melts first, thereby defining the fusing region.

[0053] As described above, the power supply device and the lead-plate 30 with fuse link function according to each embodiment, as well as the manufacturing method thereof, make it possible to specify the fuse portion by causing a specific fusing region 34 to fuse first when an overcurrent flows through the lead-plate 30. As a result, it becomes possible to inexpensively and easily control the fuse-blow position of the fuse link portion 33 on the lead-plate 30 without compromising the mechanical strength of the lead-plate 30.

[0054] In the above examples, the power supply device is attached to the electrical equipment to be driven and supplies power to the electrical equipment. When the remaining capacity of the power supply device becomes low or when the power supply device deteriorates over time, the power supply device can be replaced to continue using the electrical equipment. However, the present invention is not limited to replaceable power supply devices that mainly house secondary battery cells, but can also be applied to configurations in which secondary battery cells are housed within the housing of the electrical equipment. In this disclosure, a power supply device is sufficient as long as it houses secondary battery cells in a case, and also includes power supply devices that incorporate secondary battery cells for driving the electrical equipment within the housing of the electrical equipment itself. In other words, the present invention is not limited to replaceable power supply devices, but can also be applied to electrical equipment that incorporates secondary battery cells.

[0055] The power supply device and lead plate with fuse link function according to the present invention, as well as the manufacturing method thereof, can be suitably used as a power source for driving mobile objects such as electric carts and electric scooters. They can also be suitably used as a power source for wireless devices and portable electrical devices such as electric cleaners and power tools.

[0056] DESCRIPTION OF SYMBOLS 100...power supply device 1...secondary battery cell 1c...end surface 2...battery block 3...circuit board 4...insulating plate 10...external case 11...upper case 12...lower case 21...battery holder 22...storage tube 30...lead plate 31...base portion 32...fixing piece 33...fuse link portion 34...fusing region 35...non-fusing region 40...coating material 41...first coating material 42...second coating material 830...lead plate 833...fuse link 930...lead plate 933...fuse link 934...region that is likely to fuse d1, d1'...thickness of fusing region d2, d2'...thickness of non-fusing region d3...thickness of non-fusing region, fusing region

Claims

1. A power supply comprising: a plurality of secondary battery cells; and a lead plate electrically connecting the plurality of secondary battery cells, wherein the lead plate has a fuse link portion that cuts off the flow of electricity by melting in response to an overcurrent, wherein the fuse link portion has a melting region in part that is more likely to melt in response to an overcurrent than other regions, and the lead plate has at least a portion of the fuse link portion coated with a coating material, and wherein the melting region is thinner than the other regions of the fuse link portion.

2. A power supply device according to claim 1, wherein said fusing region is not covered with said coating material.

3. A power supply device according to claim 2, wherein the entire surface of said lead plate other than said melting area is covered with said covering material.

4. A power supply device according to any one of claims 1 to 3, wherein the length of the melting region is 10% to 70% of the length of the fuse link portion.

5. A power supply device according to any one of claims 1 to 3, wherein the coating material is a material that increases the heat capacity of the lead plate.

6. A power supply device according to any one of claims 1 to 3, wherein the coating material is an insulating material.

7. A power supply device according to any one of claims 1 to 3, wherein the coating material is black paint.

8. A power supply device comprising: a plurality of secondary battery cells; and a lead plate electrically connecting the plurality of secondary battery cells, the lead plate having a fuse link portion that cuts off current by melting in response to an overcurrent, the fuse link portion having a fusion region in a part thereof that is more likely to melt in response to an overcurrent than other regions, the lead plate being coated with a first coating material in an area other than the fusion region and the fusion region being coated with a second coating material, and the first specific heat of the first coating material being higher than the second specific heat of the second coating material.

9. A lead plate with a fuse link function for electrically connecting secondary battery cells, comprising a fuse link portion that cuts off electrical current by melting in response to an overcurrent, a part of the fuse link portion having a melting region that is more likely to melt in response to an overcurrent than other regions, at least a part of the fuse link portion of the lead plate being coated with a coating material, and a lead plate with a fuse link function in which the thickness of the melting region is thinner than the other regions of the fuse link portion.

10. A method for manufacturing a power supply device including a plurality of secondary battery cells; and a lead plate electrically connecting the plurality of secondary battery cells, the lead plate having a fuse link portion that cuts off current by melting in response to an overcurrent, the method including the steps of: coating at least a portion of the fuse link portion of the lead plate with a coating material, and forming, within the fuse link portion, a covered area that is coated with the coating material and an uncovered area that is not coated with the coating material; and connecting the lead plate to the plurality of secondary battery cells.

11. A method for manufacturing a lead plate for electrically connecting secondary battery cells, comprising the steps of: preparing the lead plate having a fuse link portion that cuts off the flow of electricity by melting in response to an overcurrent; and coating at least a portion of the fuse link portion of the lead plate with a coating material, thereby forming, within the fuse link portion, a covered area that is coated with the coating material and an uncovered area that is not coated with the coating material.

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