Battery pack, lead plate for battery pack, and method for manufacturing battery pack

Abstract

This battery pack is provided with: a plurality of secondary battery cells; at least one first lead plate connecting the plurality of secondary battery cells in series or in parallel; a circuit board connected to the first lead plate; and an exterior case housing a battery block and the circuit board, the battery block comprising the plurality of secondary battery cells connected by the at least one first lead plate. The first lead plate includes a lead body extending in one direction, and an output portion bent along a bend line at an edge of the lead body. At least one bead portion that is discontinuous across the bend line is formed along the extension direction between the lead body and the output portion.

Description

Battery pack, lead plate for battery pack, and method of manufacturing battery pack

[0001] The present disclosure relates to a battery pack, a lead plate for the battery pack, and a method for manufacturing the battery pack.

[0002] 2. Description of the Related Art Battery packs that house rechargeable secondary battery cells such as lithium-ion secondary batteries inside an exterior case and drive electrical devices are used for a variety of purposes (see, for example, Patent Documents 1 and 2).

[0003] In such battery packs, multiple secondary battery cells are connected in series or parallel via lead plates, and are further connected to a circuit board, etc. To connect the lead plates to the circuit board, during the battery pack assembly process, the lead plates are welded to a battery module that holds multiple secondary batteries in a battery holder, and then an operator manually bends the lead plates to connect them to the circuit board.

[0004] However, when connecting lead plates by hand, there is a risk of variations depending on the worker. For example, the bending position may be off depending on the worker, or external force may be applied to the lead plate, causing it to bend at a point other than the bent point, resulting in an increase in the external shape and causing problems.

[0005] On the other hand, if the lead plates are bent beforehand and the battery pack is to be assembled, it is possible to slid the circuit board from the side to assemble it. However, to enable such assembly, restrictions are imposed on the procedure and direction when assembling the circuit board and battery module, and there is a problem that this method cannot be adopted depending on the battery pack configuration.

[0006] Special Publication No. 2016-514344 Publication Patent No. 7295096

[0007] One object of the present disclosure is to provide a battery pack, a lead plate for a battery pack, and a method for manufacturing a battery pack, in which the lead plate can be easily bent by hand. Another object of the present disclosure is to provide a battery pack, a lead plate for a battery pack, and a method for manufacturing a battery pack, in which the lead plate is prevented from bending. Note that the description of these objects and objects of the present disclosure does not preclude the existence of other objects and objects. Furthermore, it is not necessary for one embodiment of the present disclosure to solve all of these objects. Furthermore, other objects can be extracted from the description of the specification, drawings, and claims of the present disclosure.

[0008] A battery pack according to one embodiment of the present disclosure includes a plurality of secondary battery cells, one or more first lead plates connecting the plurality of secondary battery cells in series or parallel, a circuit board connected to the first lead plate, a battery block in which the plurality of secondary battery cells are connected by the one or more first lead plates, and an outer case that houses the circuit board, wherein the first lead plate has a lead body extending in one direction and an output portion bent at a fold line at an end edge of the lead body, and the lead body and the output portion form one or more discontinuous bead portions along the extension direction across the fold line.

[0009] Another embodiment of the present disclosure provides a lead plate for a battery pack for connecting a plurality of secondary battery cells, the lead plate having a lead body extending in one direction and an output portion integrally formed at an end edge of the lead body via a bend line, and the lead body and the output portion form one or more discontinuous bead portions along the extension direction, sandwiching the bend line.

[0010] Furthermore, a manufacturing method of a battery pack according to another embodiment of the present disclosure is a manufacturing method of a battery pack including a plurality of secondary battery cells, one or more first lead plates connecting the plurality of secondary battery cells in series or in parallel, a circuit board connected to the first lead plate, a battery block in which the plurality of secondary battery cells are connected by the one or more first lead plates, and an outer case that houses the circuit board, the method including the steps of: forming the battery block by connecting the plurality of secondary battery cells to the first lead plate, the first lead plate having a lead body extending in one direction and an output portion integrally formed at an end edge of the lead body via a bend line, the lead body and the output portion being connected across the bend line by the first lead plate having one or more discontinuous bead portions formed along the extension direction; placing the circuit board on one surface of the battery block with the output portion extended flat from the lead body; and bending the output portion at the bend line to connect it to the circuit board.

[0011] In a battery pack according to an embodiment of the present disclosure, the first lead plate can be easily bent along the bend line, and the bead portion formed along the extension direction of the lead body provides reinforcement, thereby preventing the lead body from bending even when the output portion is bent.

[0012] 1. A perspective view showing a battery pack according to a first embodiment. 1. A perspective view of the battery pack of FIG. 1, as seen from the rear side. 2. A cross-sectional view taken along line III-III in FIG. 1. 3. A cross-sectional view taken along line IV-IV in FIG. 1. 4. An exploded perspective view of the outer case of the battery pack of FIG. 1. 5. A perspective view of the inner bag of FIG. 5, as seen from the rear side. 6. A plan view of the inner bag of FIG. 6. 7. A development view of the protective sheet of FIG. 6. 8. An exploded perspective view of the inner bag of FIG. 5. 9. An exploded perspective view of the battery module removed from the inner bag of FIG. 9. 10. An exploded perspective view of the battery module of FIG. 10. 11. An exploded perspective view of the battery module of FIG. 11, as seen from the rear side. 12. A perspective view showing a state before the output portion of the first lead plate of FIG. 11 is bent. 13. A perspective view showing a state after the output portion of the first lead plate of FIG. 13 is bent. 14. A perspective view of the first lead plate of FIG. 14, as seen from the left side. 15. An exploded perspective view showing a state in which a circuit board is attached to the battery module. 16. A perspective view showing a state in which the output portion of the first lead plate of FIG. 16 is bent. 17. A perspective view showing a state after the output portion is bent from the state of FIG. 17. 18. A plan view showing the vicinity of a bend line of the first lead plate of a battery pack according to a second embodiment. 11 is a plan view showing the vicinity of a bending line of a first lead plate of a battery pack according to a third embodiment. FIG.

[0013] The embodiments of the present disclosure may be specified by the following configurations and features.

[0014] In a battery pack according to another aspect of the present disclosure, in the above-described aspect, the one or more bead portions are composed of a main body bead formed on the lead body and an output bead formed on the output portion, and the main body bead and the output bead are spaced apart by the bend line and arranged linearly. This configuration provides the advantage of making it easier to bend the space between the main body bead and the output bead, and facilitating the positioning of the bend line.

[0015] In a battery pack according to another aspect of the present disclosure, in any of the above aspects, the one or more bead portions are configured as a pair of bead portions formed parallel to each other along the extension direction. With this configuration, the pair of bead portions sandwich the bend line at four locations with the discontinuous portions defined by the space between them, thereby enabling the bend position to be stably determined.

[0016] In a battery pack according to another aspect of the present disclosure, in any of the above aspects, the first lead-plate has a recess formed at an edge of the bend line, straddling the lead body and the output portion. With this configuration, when bending the first lead-plate along the bend line, the recess can be used as a guide to determine the bending position.

[0017] In a battery pack according to another aspect of the present disclosure, in any of the above aspects, the first lead plate includes a cell connection portion connected to the lead body via a second fold line and connected to the plurality of secondary battery cells, and the lead body and the cell connection portion are bent in advance along the second fold line. With this configuration, by using a bead portion to guide the fold line, variation in the fold line can be suppressed even when a worker manually bends the lead plate, while by bending the second fold line in advance using a machine or the like, a guide function is not required, thereby realizing a first lead plate that takes into account variations in accuracy between manual and mechanical work.

[0018] In addition, in the battery pack according to any one of the above aspects, the fold line and the second fold line intersect on their extension lines.

[0019] Furthermore, in a battery pack according to another embodiment of the present disclosure, in any of the above embodiments, the battery block includes a battery holder that houses the plurality of secondary battery cells and a board holder that holds the circuit board, and the output section is connected to the total positive or total negative terminal of the battery block on the board holder.

[0020] Furthermore, the battery pack according to another aspect of the present disclosure is any of the above-described aspects, further including one or more second lead plates that do not have the output portion and are mechanically connected to cell end faces of the plurality of secondary battery cells.

[0021] In addition, a battery pack according to another aspect of the present disclosure is any of the above-described aspects, further comprising a third lead plate that does not have the output portion, and a current fuse portion connected to the third lead plate, the board holder is installed on the battery holder, one end of the current fuse portion is connected to the third lead plate and fixed to the battery holder, and the other end is fixed to the board holder, and the third lead plate is connected to the general negative terminal or general positive terminal of the battery block on the board holder. With the above configuration, an output portion is not required for the third lead plate.

[0022] In addition, a battery pack according to another aspect of the present disclosure is any of the above-described aspects, further including a waterproof inner bag that houses the battery block. With this configuration, the bead portion prevents the lead body from bending when the first lead plate is bent, thereby preventing the curved first lead plate of the battery block housed in the inner bag from breaking the inner bag.

[0023] In yet another aspect of the battery pack manufacturing method according to the present disclosure, in any of the above aspects, in the step of configuring the battery block, the first lead plate includes a cell connection portion connected to the lead body via a second fold line and connected to the plurality of secondary battery cells, and the lead body and the cell connection portion are bent in advance along the second fold line. This allows for a bead portion to be used as a guide for the fold line, thereby suppressing variation even when a worker manually bends the lead plate. Furthermore, by bending the second fold line in advance using a machine or the like, a guide function is not required, thereby achieving a first lead plate that takes into account variations in accuracy between manual and mechanical work.

[0024] Embodiments of the present disclosure will be described below with reference to the drawings. However, the embodiments described below are merely examples for embodying the technical concepts of the present disclosure, and the present disclosure is not limited to the following. Furthermore, this specification does not in any way specify the components set forth in the claims to be those of the embodiments. The dimensions, materials, shapes, relative positions, etc. of components described in the embodiments are not intended to limit the scope of the present disclosure, and are merely illustrative examples, unless otherwise specified. The size and positional relationships of components shown in the drawings may be exaggerated for clarity. Furthermore, in the following description, the same names and symbols indicate components that are identical or of the same quality, and detailed descriptions will be omitted as appropriate. Furthermore, the elements constituting the present disclosure may be configured with the same components, such that multiple elements are shared by one component, or conversely, the functions of one component may be shared by multiple components.

[0025] The battery pack of the present disclosure 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 devices 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, or factory use, and as a driving power source for vehicles such as hybrid cars and electric automobiles. Hereinafter, a battery pack used as a driving power source for an electric motorcycle will be described as one embodiment of the present invention.

[0026] [Embodiment 1] A battery pack 100 according to embodiment 1 of the present disclosure is shown in Figures 1 to 18. In these figures, Figure 1 is a perspective view showing the battery pack 100 according to embodiment 1, Figure 2 is a perspective view of the battery pack 100 of Figure 1 as seen from the rear side, Figure 3 is a cross-sectional view taken along line III-III of Figure 1, Figure 4 is a cross-sectional view taken along line IV-IV of Figure 1, Figure 5 is an exploded perspective view of the exterior case of the battery pack 100 of Figure 1, Figure 6 is a perspective view of the inner bag 20 of Figure 5 as seen from the rear, Figure 7 is a plan view of the inner bag 20 of Figure 6, Figure 8 is a development view of the protective sheet of Figure 6, Figure 9 is an exploded perspective view of the inner bag 20 of Figure 5, Figure 10 is an exploded perspective view of the battery module 2 removed from the inner bag 20 of Figure 9, and Figure 11 is an exploded perspective view of the battery module 2 removed from the inner bag 20 of Figure 9. Fig. 12 is an exploded perspective view of the battery module 2 of Fig. 11 as seen from the rear side, Fig. 13 is a perspective view showing the state before the output portion 56 of the first lead-plate 51 of Fig. 11 is bent, Fig. 14 is a perspective view showing the state after the output portion 56 of the first lead-plate 51 of Fig. 13 is bent, Fig. 15 is a perspective view of the first lead-plate 51 of Fig. 14 as seen from the left side, Fig. 16 is an exploded perspective view showing the state when the circuit board 3 is attached to the battery module 2, Fig. 17 is a perspective view showing the state when the output portion 56 of the first lead-plate 51 of Fig. 16 is bent, and Fig. 18 is a perspective view showing the state after the output portion 56 is bent from the state of Fig. 17. The battery pack 100 shown in these figures includes an outer case 10 and an inner bag 20.

[0027] (External Case 10) The external case 10 houses the inner bag 20. The external shape of the external case 10 can be any shape that has an internal storage space. In the example shown in Figures 1 to 4, the external case 10 has a box-like shape extending in one direction. The box-shaped external case 10 is divided into an upper case 11 and a lower case 12, which are divided vertically or horizontally. This external case 10 is preferably made of a material with excellent insulating properties, such as a resin such as polycarbonate or PC-ABS alloy. It may also be made of a metal material such as aluminum or its alloy. Furthermore, the external case 10 has an internal space for housing the inner bag 20, as shown in Figure 5.

[0028] (Inner bag 20) The inner bag 20 covers the outer periphery of the battery holder 5 inside the outer case 10. The inner bag 20 is waterproof, and protects the secondary battery cells 1 housed in the outer case 10 from water. For this reason, the inner bag 20 is made of a waterproof material.

[0029] The inner bag 20 is made of a flexible material. While the inner bag 20 is shown in a box shape in the examples shown in Figures 5 to 7, 9 and 10, the shape is not limited to these and may be an irregular shape such as a bag. For such an inner bag 20, a resin having excellent heat resistance, flame retardancy, flexibility, and abrasion resistance may be used, such as a polyolefin resin or a polyethylene resin, such as a PET resin. Alternatively, a heat-shrinkable tube that shrinks when heated may be used.

[0030] Furthermore, the inner bag 20 is provided with a check valve 22 that exhausts internal gas while preventing moisture from passing through from the outside.

[0031] (Protective sheet 30) The surface of the inner bag 20 is covered with a protective sheet 30. In the example shown in Figures 6 to 9, a protective sheet 30 is attached to each of a pair of main surfaces of the inner bag 20. This protective sheet 30 is configured to continuously cover the main surface of the inner bag 20 and at least a portion of the side surface continuous with this main surface. In this way, the surface of the inner bag 20 is protected by the protective sheet 30.

[0032] The protective sheet 30 is made of an elastic material. By interposing the elastic inner bag 20 between the outer surface of the flexible inner bag 20 and the inner surface of the hard outer case 10, the inner bag 20 and the battery modules 2 housed in the inner bag 20 can be protected. Specifically, the inner bag 20 and the battery modules 2 can be protected from external forces such as impact and vibration. Furthermore, the flexible inner bag 20 can be prevented from being torn by friction caused by impact, vibration, or the like. The protective sheet 30 is made of an insulating material, such as a heat-resistant or flame-retardant rubber sheet. Preferably, a CR (chloroprene rubber) rubber sheet can be used.

[0033] (Battery Module 2) As shown in Figures 3 to 4 and 10, a battery module 2 is housed inside the inner bag 20. The battery module 2 is also called a core pack, and is composed of a battery block that houses multiple secondary battery cells 1 and a circuit board 3. As shown in Figures 10 to 12, a spacer member 40 is attached to the surface of the battery module 2.

[0034] The battery block is composed of a battery holder 5. The battery holder 5 is divided into multiple sub-holders 5a that sandwich the rechargeable battery cells 1. In the examples shown in FIGS. 3-4 and 11-12, the battery holder 5 holds a large number of cylindrical rechargeable battery cells 1 in a vertical orientation. The multiple rechargeable battery cells 1 are connected in series or parallel via lead plates 50 or the like. The number of series connections or parallel connections can be set as desired according to the required specifications. In the example shown in FIGS. 11-12, the battery module 2 uses 112 rechargeable battery cells 1, resulting in a 14-in-series x 8-in-parallel configuration, but this configuration is not limited thereto. The battery module 2 may also be composed of multiple battery blocks, each containing multiple rechargeable battery cells 1.

[0035] The battery holder 5 has multiple storage cylinders 6 that individually store the rechargeable battery cells 1. In the example shown in Figures 11 and 12, the battery holder 5 is divided into two, top and bottom, and the two storage cylinders 6 hold the rechargeable battery cells 1 from above and below. The number of battery holder sections is not limited to two, and may be three or more. The battery holder 5 can be made of resin such as polycarbonate, which has excellent insulating properties.

[0036] (Secondary battery cells 1) Each secondary battery cell 1 may be a secondary battery cell with a cylindrical or rectangular outer shape. In the examples shown in Figures 3 to 4, 11 and 12, 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 these examples, and any number and arrangement can be used as appropriate. For example, cylindrical secondary battery cells may be arranged in a matrix.

[0037] Each secondary battery cell 1 has a positive and negative electrode, which are preferably provided on one end surface of the secondary battery cell 1. The secondary battery cell 1 may be any known secondary battery, such as a lithium-ion secondary battery, a nickel-metal hydride battery, or a nickel-cadmium battery.

[0038] (Gas Release Valve) Each exterior can of the secondary battery cell 1 is provided with a gas release valve. The gas release valve opens in response to an increase in the internal pressure of the exterior can, releasing gas inside the exterior can to the outside. The gas release valve is provided on one of the cell end faces of the secondary battery cell 1. In the example shown in Figures 11 and 12, the gas release valve is provided on the positive electrode side of the secondary battery cell 1.

[0039] (Gas exhaust port 13) Meanwhile, the exterior case 10 has a gas exhaust port 13 formed in a portion thereof for releasing high-pressure gas to the outside when the gas exhaust valve of the secondary battery cell 1 is opened and the gas is released. In the example of Fig. 2, the gas exhaust port 13 is provided on the rear side of the lower case 12 of the exterior case 10. In these examples, the gas exhaust port 13 is rectangular, but the shape of the gas exhaust port 13 is not limited to rectangular and may be polygonal, such as octagonal, hexagonal, or square, or may be circular, track-shaped, elliptical, or the like.

[0040] Lead plates 50 are arranged on the side of the battery holder 5. The battery holder 5 also has guide walls 7 for determining the positions where the lead plates 50 are fixed on the side of the battery holder 5.

[0041] (Lead Plates 50) The lead plates 50 connect the electrodes on the end faces of the secondary battery cells 1 to each other, connecting multiple secondary battery cells 1 in series or parallel. In the example shown in Figures 11 and 12, the end faces of 112 secondary battery cells 1 are connected to each other with lead plates 50, and the secondary battery cells 1 are connected in a 14 series x 8 parallel configuration. Note that the number and arrangement of secondary battery cells, the number of series or parallel connections, etc. are not limited to this example, and any number and arrangement can be used as appropriate. These lead plates 50 are made of metal plates with excellent conductivity, such as aluminum plates or nickel plates.

[0042] An insulating plate may also be placed on the end surface of the lead plate 50. The insulating plate is formed to a size that covers the entire surface of the lead plate 50. An electrode window is also partially opened to expose the electrode portion of the lead plate 50. Such an insulating plate is made of a material with excellent insulating properties and fire resistance, such as mica.

[0043] (Circuit Board 3) As shown in Figures 11 and 12, the battery module 2 is connected to the circuit board 3 via lead plates 50. The circuit board 3 is equipped with a charge / discharge circuit that charges and discharges the secondary battery cells 1, a protection circuit that monitors the voltage and temperature of the secondary battery cells 1 and cuts off the current in the event of an abnormality, and other components. The circuit board 3 is made of a glass epoxy board or the like. A board holder 4 for holding such a circuit board 3 may also be provided. In the battery module 2 shown in Figures 11 and 12, the battery block is configured by installing the board holder 4 in the battery holder 5, which houses multiple secondary battery cells 1, and the board holder 4 for holding the circuit board 3 on which the common electrode terminals of the common negative terminal 8 and common positive terminal 9 of the battery pack 100 are provided.

[0044] (Current Fuse Unit 80) The current fuse unit 80 is a safety element that melts in response to an overcurrent. By providing the current fuse unit 80 as a standalone element separate from the fuse link 72 described below, the safety of the battery pack 100 is further improved. One end of the current fuse unit 80 is fixed to the battery holder 5 and connected to the lead plate 50 on the battery holder 5, and the other end is fixed to the board holder 4 and connected to one of the general electrode terminals on the circuit board 3. In this way, the current fuse unit 80 is connected between the lead plate 50 and the general negative terminal 8 or general positive terminal 9 of the battery pack 100. In the examples shown in Figures 12 and 16 to 18, the current fuse unit 80 is connected to the general positive terminal 9.

[0045] 11 and 12 includes a first lead plate 51, a second lead plate 52, and a third lead plate 53. First, the first lead plate 51 will be described.

[0046] (Bending line 55) The first lead plate 51 has a lead body 54 extending in one direction and an output portion 56 bent at a bending line 55 at an edge of the lead body 54. The lead body 54 and the output portion 56 have one or more discontinuous bead portions 60 formed along the extending direction across the bending line 55. This configuration makes it easier to bend the first lead plate 51 at the bending line 55. Furthermore, as a result of being reinforced by the bead portions 60 formed along the extending direction of the lead body 54, bending of the lead body 54 can be prevented even when the output portion 56 is bent.

[0047] When assembling a battery pack, after welding the first lead plate to the battery module, a worker must manually bend the first lead plate to connect it to the circuit board. When workers manually bend the first lead plate to connect it, there is a possibility that variations will occur depending on the worker. For example, the bending position may differ depending on the worker or the production lot. Furthermore, when external force is applied to the first lead plate, it may bend at a point other than the bend, resulting in an increased external shape and causing problems.

[0048] On the other hand, it is possible to assemble the battery pack with the first lead plate bent in advance, but in this case, the circuit board needs to be slid sideways when assembled, and to enable such assembly, restrictions are imposed on the procedure and direction when assembling the circuit board and battery module, etc. This has led to the problem that this method cannot always be adopted depending on the battery pack configuration.

[0049] Therefore, in this embodiment, by using the bead portion 60 as described above to regulate the bending position, such variations can be reduced and the position of the bending line 55 can be controlled with precision, thereby achieving a high-quality battery pack 100.

[0050] Furthermore, by using the bead portion 60 to prevent the lead body 54 from bending when the first lead plate 51 is bent, it is possible to prevent the curved first lead plate 51 of the battery block stored in the inner bag 20 from breaking the inner bag 20.

[0051] (Bead portion 60) The lead body 54 and the output section 56 form one or more discontinuous bead portions 60 along the extension direction, sandwiching the bend line 55. In the example shown in Figures 13 and 14, the bead portion 60 is composed of a body-side bead 61 formed on the lead body 54 and an output-side bead 62 formed on the output section 56 side. The body-side bead 61 and the output-side bead 62 are arranged linearly and are separated by the bend line 55. This has the advantage of making it easier to bend the space between the body-side bead 61 and the output-side bead 62, as shown in Figures 14 and 15, and facilitating the positioning of the bend line 55.

[0052] It is also preferable that the bead portions 60 are a pair of bead portions 60 formed parallel to each other along the extension direction, so that the bend line 55 is sandwiched at four points by the discontinuous portions defined by the pair of bead portions 60 at a distance, thereby making it possible to stably define the bending position.

[0053] Furthermore, the bead portion 60 also contributes to reinforcing the lead plate 50. The body-side bead 61 extends substantially over the entire length of the lead body 54. The output-side bead 62 also extends along the output portion 56. By extending the bead portion 60 in this manner, a resistance is generated in a direction intersecting the bead portion 60, and it is possible to prevent the lead plate 50 from being bent into an unintended shape due to the application of unnecessary stress when bending by hand.

[0054] Each bead 60 is formed by processing the surface of the lead plate 50 into a convex or concave shape. Such a bead 60 can be easily formed by press working or the like. Alternatively, the bead may be made of a separate member such as a metal and attached to the surface of the lead plate by welding or bonding.

[0055] (Cell connection portion 70) The first lead plate 51 shown in Fig. 13 includes a lead body 54, an output portion 56, and a cell connection portion 70. The cell connection portion 70 is physically connected to multiple secondary battery cells 1, and connects the multiple secondary battery cells 1 in series and / or parallel. In the example of Fig. 13, the cell connection portion 70 connects the multiple secondary battery cells 1 in parallel. For this reason, the cell connection portion 70 includes a fuse link 72 for connecting to the cell end face of the secondary battery cell 1. When an overcurrent flows through the lead plate 50, the fuse link 72 reacts to this and melts with Joule heat, thereby interrupting the current flow.

[0056] (Output section 56) On the other hand, the output section 56 is connected to the total positive or negative terminal 8 of the battery block. A connection hole 57 is opened in the output section 56 to connect to the total positive or negative terminal 8. The examples in Figures 11 to 12 and 18 show an example in which the output section 56 is connected to the total negative terminal 8.

[0057] (Second fold line 74) The cell connection portion 70 is connected to the lead body 54 via a second fold line 74. The lead body 54 and the cell connection portion 70 are bent in advance via the second fold line 74. With this configuration, the bead portion 60 is used to guide the fold line 55, thereby suppressing variation even when a worker manually bends the lead body 54. On the other hand, the second fold line 74 is bent in advance using a machine or the like, eliminating the need for a guide function, thereby realizing a first lead plate 51 that takes into account variations in accuracy between manual and mechanical work.

[0058] The fold line 55 and the second fold line 74 intersect at their extensions. By intersecting the fold line 55 and the second fold line 74 in this manner so as to move them away from a parallel state, it is possible to avoid or suppress a situation in which excess stress is transmitted to the already bent second fold line 74 when the sheet is manually bent at the fold line 55. In the example of Fig. 13, the extension line of the fold line 55 and the extension line of the second fold line 74 are made to intersect almost perpendicularly.

[0059] (Recess 58) Furthermore, first lead plate 51 has recess 58 formed at the edge of bend line 55, straddling lead body 54 and output portion 56. That is, recess 58 is formed on each end of bend line 55. This makes it possible to determine the bending position by using recess 58 as a guide when bending first lead plate 51 along bend line 55.

[0060] (Second lead-plate 52) The second lead-plate 52 does not have an output section. Each second lead-plate 52 is mechanically connected to the cell end faces of multiple secondary battery cells 1, connecting them in series and / or parallel. In the example shown in FIGS. 11 and 12 , the second lead-plate 52 connects multiple secondary battery cells 1 in parallel. In other words, the second lead-plate 52 is configured as the cell connection portion 70 of the first lead-plate 51. In the example shown in FIGS. 11 to 12 , the second lead-plate 52 has two rows of seven fuse links 72 that connect to the cell end faces, connecting a total of 14 secondary battery cells 1. Meanwhile, the cell connection portion 70 of the first lead-plate 51 has one row of seven fuse links 72. In addition, in the example shown in FIGS. 11 and 12 , the battery module 2 has six second lead-plates 52 on the upper surface and seven second lead-plates 52 on the lower surface. An intermediate connection portion 76 is provided at the edge of each second lead-plate 52 to connect to the circuit board 3 and detect the intermediate potential. Each intermediate connection portion 76 is bent into an L-shape at an edge of the second lead-plate 52 .

[0061] (Third Lead Plate 53) The third lead plate 53 is a member for connecting to the current fuse unit 80. The third lead plate 53 does not have an output unit 56. However, the third lead plate 53 has a cell connection unit 70 similar to the first lead plate 51, and is mechanically connected to the cell end faces of multiple secondary battery cells 1, connecting them in series and / or in parallel. In the example of FIGS. 11 and 12 , the cell connection unit 70 of the third lead plate 53 connects multiple secondary battery cells 1 in parallel. In addition to the cell connection unit 70, the third lead plate 53 also has a third lead body 77 and a fuse connection unit 79 for connecting to the current fuse unit 80. The third lead body 77 and the fuse connection unit 79 are bent at a third fold line 78. It is preferable that the third fold line 78 is not bent by hand, but is bent in advance by machining or the like. 16 and 17 , since the fuse connection portion 79 is connected to the current fuse portion 80 in advance, and the other terminal of the current fuse portion 80 is connected to the circuit board 3, the third lead-plate 53 does not require a manual bending mechanism as in the first lead-plate 51. By eliminating the need for manual bending in this way, the third fold line 78 does not require a guide mechanism such as the bead portion 60 as shown in FIG.

[0062] The third lead plate 53 is connected to the battery block's negative terminal 8 or positive terminal 9. In the examples shown in Figures 12, 16 to 18, etc., the third lead plate 53 is connected to the positive terminal 9.

[0063] [Embodiment 2] In the above-described embodiment 1, an example in which two bead portions 60 are provided in parallel has been described. However, the present disclosure is not limited to this configuration, and three or more bead portions may be provided. Alternatively, a single bead portion may be provided. Such an example is shown in the enlarged plan view of FIG. 19 as a lead plate 50B of a battery pack according to embodiment 2. In this figure, components similar to those in embodiment 1 described above are designated by the same reference numerals, and detailed descriptions thereof will be omitted where appropriate.

[0064] 19 has only one bead portion 60B extending in the longitudinal direction while forming a space by discontinuing the main body bead 61B and the output side bead 62B at a bend line 55B. In this case, it is preferable to position the bead portion 60B approximately at the center in the width direction of the lead body 54. Note that since there is only one space between the main body bead 61B and the output side bead 62B, it is preferable to form recesses 58 on both sides of the bend line 55B to prevent the bend line 55B from becoming slanted when the lead is bent by hand.

[0065] [Embodiment 3] While the above examples have been described in which the bead portions are linear, the present disclosure does not limit the shape of the bead portions to linear shapes, and the bead portions may have any shape that allows for a defined bending position, such as a dotted shape, an L-shape, or a V-shape. For example, in the lead-plate 50C of a battery pack according to embodiment 3 shown in Fig. 20, dotted bead portions 64 are added to the top and bottom of the opposing ends of the first lead-plate 51C between the main-side bead 61C and the output-side bead 62C that constitute the linear bead portion 60C. The addition of such bead portions 64 makes it easier to define the bending line 55C perpendicular to the bead portion 60C, which can improve the accuracy of manual bending and contribute to stabilizing quality.

[0066] [Manufacturing Method of Battery Pack] A manufacturing method of the battery pack 100 will now be described. First, a plurality of secondary battery cells 1 are connected with a first lead plate 51 to form a battery module 2. The first lead plate 51 has a lead body 54 extending in one direction and an output portion 56 integrally formed at an edge of the lead body 54 via a fold line 55. The lead body 54 and the output portion 56 form one or more discontinuous bead portions 60 along the extension direction, sandwiching the fold line 55. Note that the lead body 54 and the cell connection portion 70 of the first lead plate 51 are preferably bent in advance via a second fold line 74 by machining or the like.

[0067] Next, as shown in FIG. 16, the circuit board 3 is placed on one surface of the battery module 2 with the output section 56 extended from the lead body 54 in a plane.

[0068] 17, the output portion 56 is then bent at the bend line 55 to connect to the circuit board 3. The lead body 54 and the output portion 56 form a discontinuous bead portion 60 on either side of the bend line 55, making it easier to manually bend the first lead plate 51 at the bend line 55. Furthermore, the bead portion 60 formed along the extension direction of the lead body 54 provides reinforcement, preventing the lead body 54 from bending even when the output portion 56 is bent. In this way, the battery module 2 shown in FIG. 18 is obtained.

[0069] (Spacer Member 40) Spacer members 40 are provided on the side of the battery holder 5. The spacer members 40 are interposed between the exterior case 10 and the battery module 2. As shown in FIG. 4 , the spacer members 40 form a space between the inner surface of the exterior case 10 and the side of the battery holder 5. This space functions as a gas discharge space GS for discharging gas released from the gas discharge valve. The spacer members 40 are made of a heat-resistant material. This prevents the spacer members 40 from immediately melting due to high heat, ensuring the gas discharge space GS, even in the unlikely event that high-temperature, high-pressure gas is discharged from the gas discharge valve. CR (chloroprene rubber)-based rubber can be used for such spacer members 40.

[0070] Furthermore, the spacer member 40 is made of a flexible material. With this configuration, even if an external force is applied to the battery pack 100, the spacer member 40 can absorb the external force and protect the battery holder 5.

[0071] The spacer members 40 are preferably provided on the cell end faces 1b of the multiple secondary battery cells 1 that do not have gas release valves. If the spacer members 40 were provided on the cell end faces 1a that have gas release valves, in the event that high-temperature, high-pressure gas were to be released through the gas release valves, the spacer members 40 would hinder the gas release, preventing it from being smoothly released to the outside, and the pressure inside the outer can could build up and cause it to burst. Therefore, by positioning the spacer members 40 away from the cell end faces 1a that have gas release valves, even if high-temperature, high-pressure gas were to be released through the gas release valves, the spacer members 40 would not hinder the release of the gas, and smooth gas release can be maintained even when the spacer members 40 are attached to the battery holder 5.

[0072] The spacer member 40 is fixed to the side of the battery holder 5 by an adhesive layer. The adhesive layer can be double-sided tape. Alternatively, the spacer member 40 can be fixed by adhesive or the like.

[0073] It is also preferable to fix the spacer members 40 to the side surfaces of the battery holder 5 along the guide walls 7. This allows the guide walls 7, which position the lead plates 50, to also be used to position the spacer members 40.

[0074] The spacer members 40 are arranged so that the cell end faces are flush with each other, and continuously cover the cell end faces of a series of secondary battery cells 1. Therefore, the spacer members 40 are formed according to the stacking pattern of the secondary battery cells 1. For example, as shown in Figures 11 and 12, the spacer members 40 are formed in a wavy shape in a plan view.

[0075] 11 and 12, multiple spacer members 40 are fixed at a distance from each other on the side surfaces of the battery cells. Furthermore, it is preferable that the spacer members 40 have the same shape on each side surface of the battery holder 5. Additionally, it is preferable that the spacer members 40 on each side surface are mirror images. This allows the same spacer member 40 to be used on both the left and right sides by flipping the spacer member 40, thereby reducing the number of parts required when assembling the battery pack 100.

[0076] Furthermore, the spacer member 40 extends to cover the continuous cell end faces on the side of the battery holder 5. Additionally, a space is formed between the spacer member 40 and the edge of the side of the battery holder 5. This configuration ensures that the side of the battery holder 5 is not completely partitioned by the spacer member 40. By creating a space, if gas is to be released from the gas release valve, the spacer member 40 will not block the gas being released along the side of the battery holder 5. This allows smooth gas release to be maintained even when the spacer member 40 is attached to the battery holder 5.

[0077] The spacer members 40 also protect the inner bag 20. The spacer members 40 are formed in a continuous line on the side of the battery holder 5 to cover the continuous cell end faces. However, it is preferable not to cover the cell end faces located at the ends with the spacer members 40. This allows the battery holders 5 to be housed in the inner bag 20 for waterproofing, while not covering the cell end faces located at the ends, thereby preventing the inner bag 20 from being subjected to excessive load and breaking.

[0078] The protective sheet 30 is configured to cover the cell end surface 1a where the gas release valve is located. By using the protective sheet 30, which covers the battery holder 5 to improve impact resistance, to cover the cell end surface 1a where the gas release valve is located, even if high-temperature, high-pressure gas is released from the gas release valve of one of the secondary battery cells 1, the gas will not be immediately released from the battery pack, preventing a situation in which the flame caused by the gas ignition would leak directly outside the battery pack.

[0079] Generally, in a battery pack, if any abnormality occurs in any of the secondary battery cells housed in the outer case and high-pressure gas is generated inside the outer case, a gas release valve provided in the outer case is configured to open. In this case, a structure is required to safely release the high-pressure gas released inside the outer case to the outside.

[0080] However, it has not been easy to realize such a structure. In particular, in recent years, there has been a demand for battery packs to be smaller and lighter, while at the same time there has been a demand for cost reduction, and it has not been easy to secure the space and cost required to add a structure for safely venting exhaust gas. In contrast, this embodiment has the advantage that the protective sheet 30, which is intended to improve impact resistance, can also be used as a member for suppressing the occurrence of fire leakage while ensuring the gas vent space GS.

[0081] (First openings 31) Furthermore, the protective sheet 30 has multiple first openings 31. As shown in Fig. 7 , each of the first openings 31 exposes a portion of each of the multiple cell end faces 1b that do not have a gas release valve. As a result, in the unlikely event that high-temperature, high-pressure gas is released from a gas release valve of one of the secondary battery cells 1, the gas is not released directly from the cell end face 1a where the gas release valve is provided, but is instead moved to the position of another cell end face 1b that does not have a gas release valve, i.e., to the position of the first opening 31, and then released. This lengthens the gas movement path, weakens the gas's force and temperature, and is expected to allow it to be released more safely to the outside.

[0082] Furthermore, the first opening 31 exposes, from the protective sheet 30, a plurality of cell end faces 1b that are not provided with spacer members 40, among the plurality of cell end faces 1b that are not provided with gas release valves. In Fig. 7, the spacer members 40 provided on the inside of the inner bag 20 are indicated by dashed lines. With this configuration, the cell end faces 1a that are provided with gas release valves are closed with the protective sheet 30, which makes it possible to both regulate and release gas while suppressing the occurrence of fire leaks.

[0083] The spacer member 40 forms the gas discharge space GS, and is therefore made thicker than the protective sheet 30. On the other hand, the protective sheet 30 is made thin so that it can be easily attached to the surface of the inner bag 20 and also prevents the battery module 2 from becoming thick.

[0084] (Second openings 32) Furthermore, the protective sheet 30 has a plurality of second openings 32 formed along the boundary between the main surface and the side surface connected to the main surface, as shown in Fig. 8. This makes it possible to make the protective sheet 30, which is made of an elastic material and is difficult to fold, easier to fold by forming a plurality of second openings 32 at intervals along the boundary line between the main surface and the side surface, as shown in Fig. 9.

[0085] It is preferable that each of the second openings 32 is smaller than each of the first openings 31. This increases the area of ​​the first openings 31, which are mainly responsible for discharging gas, and enables smooth gas discharge.

[0086] 8 , the protective sheet 30 preferably has a plurality of third openings 33 formed at positions corresponding to the check valves 22 of the inner bag 20. This allows gas generated inside the inner bag 20 to be discharged to the outside through the check valves 22 and the third openings 33.

[0087] It is preferable that each of the third openings 33 be smaller than each of the second openings 32. This allows the area of ​​the first openings 31, which are used to urgently discharge gas that is suddenly generated, to be larger than the area of ​​the third openings 33, which are used to discharge a relatively small amount of gas, making it possible to discharge gas smoothly.

[0088] In the above example, the battery pack is used as a power source for an electric scooter. However, the present disclosure is not limited to this. The battery pack can also be used for other purposes, such as attaching it to an electric device to be driven and supplying power to the electric device. Examples of electric devices include mobile objects such as electric vehicles and electric carts, as well as portable electric devices. In such electric devices, when the remaining capacity of the battery pack becomes low or the battery pack deteriorates over time, the battery pack can be replaced to continue using the electric device. However, the present disclosure is not limited to replaceable battery packs that mainly house secondary battery cells, but can also be applied to battery packs in which secondary battery cells are housed within the housing of the electric device. In the present disclosure, a battery pack is defined as a battery pack that houses secondary battery cells in a case, and also includes battery packs in which secondary battery cells for driving the electric device are built into the housing of the electric device itself. In other words, the present disclosure is not limited to replaceable battery packs, but can also be applied to electric devices that house secondary battery cells.

[0089] The battery pack, lead plate for the battery pack, and method for manufacturing the battery pack according to the present invention can be suitably used as a driving power source for mobile objects such as electric scooters, electric carts, and assisted bicycles, as a power source for radios, and as a power source for portable electrical equipment such as electric cleaners and power tools, as a backup power source for servers, and as a stationary power storage device for home, office, and factory use.

[0090] DESCRIPTION OF SYMBOLS 100...Battery pack 1...Secondary battery cell 1a...Cell end surface provided with gas release valve 1b...Cell end surface not provided with gas release valve 2...Battery module 3...Circuit board 4...Board holder 5...Battery holder 5a...Sub-holder 6...Storage tube 7...Guide wall 8...General negative terminal 9...General positive terminal 10...Outer case 11...Upper case 12...Lower case 13...Gas release port 20...Inner bag 22...Check valve 30...Protective sheet 31...First opening 32...Second opening 33...Third opening 40...Spacer member 50, 50B, 50C...Lead plate 51, 51B, 51C...First lead plate 52...Second lead plate 53...Third lead plate 54...Lead body 55, 55B, 55C...Bending line 56...Output portion 57...Connection hole 58...Recess 60, 60B, 60C, 64... Bead portion 61, 61B, 61C... Main body side bead 62, 62B, 62C... Output side bead 70... Cell connection portion 72... Fuse link 74... Second bend line 76... Intermediate connection portion 77... Third lead main body 78... Third bend line 79... Fuse connection portion 80... Current fuse portion GS... Gas discharge space

Claims

1. A battery pack comprising: a plurality of secondary battery cells; one or more first lead plates connecting the plurality of secondary battery cells at least in either series or parallel; a circuit board connected to the first lead plate; a battery block in which the plurality of secondary battery cells are connected by the one or more first lead plates; and an outer case that houses the circuit board, wherein the first lead plate has a lead body extending in one direction and an output portion bent at a bend line at an end edge of the lead body, and the lead body and the output portion have one or more bead portions that are discontinuous across the bend line and extend along the extension direction of the lead body and the output portion.

2. A battery pack as claimed in claim 1, wherein each of said one or more bead portions is composed of a main body bead formed on said lead body and an output side bead formed on said output portion side, and said main body side bead and said output side bead are spaced apart by said bend line and arranged in a straight line.

3. A battery pack according to claim 1, wherein the one or more bead portions are composed of a pair of bead portions formed parallel to each other along the extension direction.

4. A battery pack according to claim 1, wherein the first lead plate has a recess formed at the edge of the bent line, straddling the lead body and the output section.

5. A battery pack as claimed in claim 1, wherein the first lead plate is provided with a cell connection portion connected to the lead body via a second fold line and connected to the plurality of secondary battery cells, and the lead body and the cell connection portion are bent in advance via the second fold line.

6. A battery pack according to claim 5, wherein the fold line and the second fold line intersect on extensions of the fold line and the second fold line, respectively.

7. A battery pack as claimed in claim 1, wherein the battery block comprises a battery holder that houses the plurality of secondary battery cells and a board holder that holds the circuit board, and the output section is connected to the total positive terminal or the total negative terminal of the battery block on the board holder.

8. A battery pack according to claim 7, further comprising one or more second lead plates that do not have the output section and are mechanically connected to the cell end faces of the plurality of secondary battery cells.

9. A battery pack as claimed in claim 8, further comprising: a third lead plate not having the output section; and a current fuse section connected to the third lead plate; wherein the board holder is installed on the battery holder; the current fuse section has a first end connected to the third lead plate and fixed to the battery holder, and a second end fixed to the board holder; and the third lead plate is connected to the negative terminal or the positive terminal of the battery block on the board holder.

10. A battery pack according to any one of claims 1 to 9, further comprising a waterproof inner bag for housing the battery block.

11. A lead plate for a battery pack for connecting multiple secondary battery cells, comprising: a lead body extending in one direction; and an output portion integrally formed at the end edge of said lead body via a bend line, wherein said lead body and said output portion are formed with one or more discontinuous bead portions along the extension direction, sandwiching said bend line.

12. A method for manufacturing a battery pack comprising: a plurality of secondary battery cells; one or more first lead plates connecting the plurality of secondary battery cells in series or in parallel; a circuit board connected to the first lead plates; a battery block in which the plurality of secondary battery cells are connected by the one or more first lead plates; and an outer case that houses the circuit board, the method comprising the steps of: connecting the plurality of secondary battery cells to a lead body extending in one direction; and an output portion integrally formed at an end edge of the lead body via a bend line, the lead body and the output portion being connected to each other by the first lead plate that forms one or more discontinuous bead portions along the extension direction of the lead body and the output portion, with the bend line in between, to form the battery block; placing the circuit board on one surface of the battery block with the output portion extending flat from the lead body; and bending the output portion at the bend line to connect it to the circuit board.

13. A method for manufacturing a battery pack as described in claim 12, wherein, in the step of constructing the battery block, the first lead plate has a cell connection portion that is connected to the lead body via a second fold line and that is connected to the multiple secondary battery cells, and the lead body and the cell connection portion are bent in advance via the second fold line.

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