Battery pack

Abstract

This battery pack is provided with: a plurality of secondary battery cells which are arranged in a posture parallel to each other in the longitudinal direction, each secondary battery cell having end-surface electrodes at both ends, and at least one of the end-surface electrodes serving as a first electrode to which a relief valve is provided; a battery holder for holding the plurality of secondary battery cells; a conductive lead plate that connects the end surface electrodes of adjacent secondary battery cells to each other; and an insulating plate covering the surface of the lead plate, the lead plate having a lead opening window formed between the first electrodes of the adjacent secondary battery cells, and the insulating plate having an insulating opening window formed at a position corresponding to the lead opening window.

Description

Technical Field

[0001] The present disclosure relates to battery packs. Background Art

[0002] A battery pack formed by connecting multiple secondary battery cells in series or in parallel is used as a power source for portable electric devices such as portable speakers, electric cleaners, and electric tools, or as a backup power source for servers for stationary power storage purposes, a power source for home use, office use, and factory use, and is also used as a driving power source for power-assisted bicycles, electric carts, electric scooters, or hybrid vehicles, electric vehicles, and other vehicles. Such a battery pack is mostly held in an adjacent posture by a battery holder, and adjacent secondary battery cells are connected by welding with a plate-shaped lead plate (for example, see Patent Document 1).

[0003] For the secondary battery cells used in such battery packs, lithium-ion secondary batteries are generally used, but lithium-ion secondary battery cells may cause unsafe events accompanied by smoke and fire due to some abnormality. Therefore, a safety valve is provided on the end face (for example, the end face on the positive electrode side) of the electrode formed by the lithium-ion secondary battery cell, and is configured so that when the internal pressure of the outer tank of the secondary battery cell increases, the safety valve opens and releases the internal high-pressure gas to the outside. However, assuming that an unsafe event occurs in any secondary battery cell, it is believed that the high-temperature gas, flame, electrolyte and other discharges released from the safety valve of the secondary battery cell are transferred through the lead plate and moved to other adjacent secondary battery cells, which may be damaged and spread to the fire.

[0004] Prior Art Literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2012-033464 Summary of the invention

[0007] One of the objects of the present disclosure is to provide a battery pack in which adjacent secondary battery cells are connected with a lead plate, and in which even if an abnormality occurs in one secondary battery cell, damage to other adjacent secondary battery cells can be suppressed.

[0008] A battery pack involved in one embodiment of the present invention comprises: a plurality of secondary battery cells having end surface electrodes at both ends, at least one of the end surface electrodes being used as a first electrode provided with a safety valve, and arranged in a posture parallel to the length direction; a battery holder for holding the plurality of secondary battery cells; a conductive lead plate for connecting the end surface electrodes of adjacent secondary battery cells to each other; and an insulating insulating plate for covering the surface of the lead plate, the lead plate having lead opening windows formed between the first electrodes of adjacent secondary battery cells, and the insulating plate having insulating opening windows formed at positions corresponding to the lead opening windows.

[0009] According to the battery pack involved in one aspect of the present invention, since the first electrodes of adjacent secondary battery cells are not completely blocked by lead plates and lead opening windows are provided, even if any secondary battery cell abnormally releases high-temperature gases and other exhaust gases, it is possible to reduce the adverse effects on other adjacent secondary battery cells by releasing them to the outside through the open space. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a perspective view showing the appearance of a battery pack according to an embodiment of the present invention.

[0011] Figure 2 yes Figure 1 A vertical cross-sectional view of a battery pack taken along line II-II.

[0012] Figure 3 It is shown Figure 1 A three-dimensional diagram of the manufacturing process of a battery pack.

[0013] Figure 4 yes Figure 3 An exploded perspective view of a battery assembly of a battery pack.

[0014] Figure 5 Yes Figure 4 An exploded perspective view of a battery assembly with the lead plate removed.

[0015] Figure 6 Yes Figure 5 An exploded perspective view of a battery assembly after the battery holder is disassembled.

[0016] Figure 7 yes Figure 4 Front view of the battery assembly shown.

[0017] Figure 8 yes Figure 4 The shown figure is an enlarged perspective view of the main parts of the battery assembly.

[0018] Fig. 9 yes Figure 4The main parts of the battery assembly shown are enlarged and exploded perspective views.

[0019] Fig.10 yes Figure 2 An enlarged cross-sectional view of the main parts of the battery pack is shown.

[0020] Fig.11 This is a schematic cross-sectional view showing a state in which waste is discharged from a secondary battery cell of a conventional battery pack.

[0021] Fig.12 This is a schematic cross-sectional view showing a state where waste is discharged from a secondary battery cell of the battery pack of the present invention. DETAILED DESCRIPTION

[0022] The embodiments of the present invention can also be identified by the following structures and features.

[0023] Regarding the battery pack involved in another embodiment of the present invention, it is also possible that in the above embodiment, the lead opening window extends in a second direction, and the second direction intersects with a first line that connects the centers of the first electrodes of adjacent secondary battery cells in the shortest manner. According to the above structure, since the lead opening window is provided to extend in the second direction intersecting the first line, the discharge moving along the first line can efficiently pass through the lead opening window and be discharged to the outside.

[0024] Regarding the battery pack involved in another aspect of the present invention, in the above aspect, the lead plate may be provided with conductive parts on both sides of the lead opening window. According to the above structure, by providing the conductive parts on both sides of the lead opening window opened in the lead plate, the area of ​​the conduction path lost by providing the lead opening window on the first line can be obtained, thereby reducing the resistance of the lead plate.

[0025] In a battery pack according to another aspect of the present invention, in the above aspect, the insulating opening window may be opened in a slit shape overlapping with the lead wire opening window.

[0026] Regarding the battery pack involved in another embodiment of the present invention, it can also be that in the above embodiment, the lead plate has: a plurality of stacked parts stacked on the surface of the battery holder; and a plurality of welding parts connected between the plurality of stacked parts and connected to the first electrode, and a lead opening window is provided in the stacked part.

[0027] In another embodiment of the present invention, the battery pack may be formed by bending a metal plate to alternately provide a plurality of stacked portions and a plurality of welded portions having steps relative to the stacked portions. According to the above structure, by bending the metal plate, the plurality of stacked portions and the plurality of stacked portions can be simply and easily formed into a shape having steps.

[0028] Regarding the battery pack involved in another embodiment of the present invention, in the above embodiment, the battery holder may be formed into a box shape, and the first electrodes of the plurality of secondary battery cells may be arranged on the first surface of the box shape, and the battery holder may be provided with a connection window for exposing the first electrodes in an opening on the first surface, and the connection window may be an internal shape capable of embedding the welding portion of the lead plate. According to the above structure, by embedding the welding portion of the lead plate into the connection window of the battery holder, the lead plate can be simply and easily positioned and arranged at a fixed position of the battery holder.

[0029] Regarding the battery pack involved in another embodiment of the present invention, it can also be that in the above embodiment, the battery pack has a plurality of parallel units, the parallel units arrange the secondary battery cells in a parallel posture and connect them in parallel, the plurality of parallel units are connected in series with each other to form a battery block in which the plurality of secondary battery cells held by the battery holder are connected in series and parallel, and the lead plate is set as an output lead plate connected to the output side of the battery block.

[0030] Regarding the battery pack involved in another embodiment of the present invention, it is also possible that, in the above embodiment, the battery holder is formed into a box shape, the first electrodes of the plurality of secondary battery cells are arranged on the first surface of the box shape, the battery holder has a positioning rib on the first surface for placing the outer peripheral edge of the lead plate in abutment at a fixed position, and the positioning rib is used as a control wall to suppress the movement of the discharge discharged from the safety valve of the first electrode. According to the above structure, the lead plate can be arranged at a fixed position of the battery holder via the positioning rib, and the positioning rib is used as a control wall to control the movement of the discharge discharged from the safety valve of the first electrode.

[0031] Regarding the battery pack involved in another embodiment of the present invention, it can also be that in the above embodiment, the battery holder is formed into a box shape, the first electrodes of multiple secondary battery cells are arranged on the first surface forming the box shape, the battery holder is provided with a positioning protrusion protruding from the surface on the first surface, and the insulating plate is formed with a positioning hole for the positioning protrusion to be inserted, and the insulating plate can be positioned on the first surface via the positioning hole and the positioning protrusion. The above insulating plate can make the positioning hole and the positioning protrusion fit together to arrange the insulating plate in a fixed position of the battery holder. In this way, the insulating plate arranged in the fixed position of the battery holder can arrange the insulating opening window at an accurate position relative to the lead opening window.

[0032] Hereinafter, the embodiments of the present invention will be described based on the accompanying drawings. However, the embodiments shown below are examples for concretizing the technical ideas of the present invention, and the present invention is not limited to the following. In addition, this specification does not limit the components shown in the claims to the components of the embodiments. In particular, the size, material, shape, relative configuration, etc. of the structural parts recorded in the embodiments are not intended to limit the scope of the present invention to this, as long as there is no specific record, but are just simple illustrative examples. In addition, for the sake of clarity, the size, positional relationship, etc. of the components shown in the drawings are sometimes exaggerated. Further, in the following description, for the same name, symbol, the same or homogeneous components are represented, and detailed description is appropriately omitted. Further, the elements constituting the present invention can be a method in which the same components constitute multiple elements so that one component can be used as multiple elements. On the contrary, it can also be realized by multiple components sharing the function of one component.

[0033] The battery pack of the present invention can be used as a power source for electrical equipment such as speakers, electric cleaners, and electric tools, or as a backup power source for servers, a power supply device for home use, office use, and factory use in a stationary power storage purpose, and can also be used as a driving power source for power-assisted bicycles, electric scooters, electric carts, or hybrid vehicles, electric vehicles, and other vehicles. Below, as one embodiment of the present invention, a battery pack used as a power source for a wireless speaker is described.

[0034] [Implementation Method 1]

[0035] The battery pack 100 according to the first embodiment of the present invention is shown in FIG. Figures 1 to 10 . Figure 1 The figure shows the appearance of the battery pack. Figure 2 Shows Figure 1 A vertical cross-sectional view of the battery pack along line II-II, Figure 3 Shown Figure 1 A three-dimensional diagram of the manufacturing process of a battery pack. Figure 4 Shows Figure 3 An exploded perspective view of a battery assembly of a battery pack, Figure 5 Shows the Figure 4 An exploded perspective view of a battery assembly with the lead plate removed. Figure 6 Shows the Figure 5 An exploded perspective view of a battery assembly after the battery holder is disassembled, Figure 7 Shows Figure 4 The front view of the battery assembly shown, Figure 8 as well as Fig. 9 Shows Figure 4 The main part of the battery assembly is shown in an enlarged perspective view and an enlarged exploded perspective view of the main part. Fig.10Shows Figure 2 The battery pack 100 shown in these figures comprises: a plurality of secondary battery cells 1, at least one of the end electrodes 11 being a first electrode 11A provided with a safety valve, and arranged in a posture parallel to the longitudinal direction; a battery holder 2 for holding the plurality of secondary battery cells 1; a conductive lead plate 3 for connecting the end electrodes 11 of adjacent secondary battery cells 1; and an insulating insulating plate 5 for covering the surface of the lead plate 3, the lead plate 3 having a lead opening window 30 formed between the first electrodes 11A of adjacent secondary battery cells 1, and the insulating plate 5 having an insulating opening window 53 formed at a position corresponding to the lead opening window 30.

[0036] (Battery assembly 10)

[0037] Figures 1 to 10 The battery pack 100 shown has lead plates 3 fixed to both end surfaces of a battery holder 2 that accommodates a plurality of secondary battery cells 1, and a circuit substrate 4 is arranged on the upper portion of the battery holder 2 to form a battery assembly 10. On the outer peripheral surface of the battery assembly 10, the surface of the lead plate 3 is covered by an insulating plate 5, the upper surface of the battery assembly 10 is covered by an insulating member 6, and the battery assembly 10 whose surface is insulated is covered by an outer sheet 7.

[0038] (Secondary battery cell 1)

[0039] Each secondary battery cell 1 is a cylindrical secondary battery cell whose outer can is cylindrical. As an example, the secondary battery cell 1 can use a component that contains an electrode body in a metal outer can, fills the electrolyte, and hermetically seals the opening of the outer can with a sealing plate. The cylindrical secondary battery cell is provided with end surface electrodes 11 at both ends in the length direction. The secondary battery cell 1 uses the bottom surface of the outer can as the two end surfaces and the electrodes provided in the center of the sealing plate as positive and negative electrodes. In addition, the secondary battery cell 1 uses at least one of the end surface electrodes 11 at both ends as a first electrode 11A provided with a safety valve (not shown). The secondary battery cell 1 in the figure is formed by a convex electrode arranged in the center of the sealing plate to form a first electrode 11A provided with a safety valve, and another end surface electrode 11 is formed by the bottom surface electrode of the outer can as a second electrode 11B. The safety valve opening is a component for releasing the internal gas when the internal pressure of the outer can rises. Therefore, all secondary batteries that discharge the exhaust of the gas lamp when the internal pressure rises and the safety valve opens can be used for the secondary battery cell 1. In addition, the safety valve is generally set on the positive electrode side, but the present invention does not limit the location of the safety valve to the positive electrode side, and can also be set at other locations, such as the negative electrode side.

[0040] Such a secondary battery cell 1 can suitably utilize a non-aqueous electrolyte secondary battery with high energy efficiency, such as a lithium-ion secondary battery. However, the battery pack of the present invention does not limit the secondary battery cell to a lithium-ion secondary battery, nor does it limit the secondary battery cell to a cylindrical battery. For the secondary battery cell, all rechargeable batteries, such as nickel-hydrogen batteries, nickel-cadmium batteries, etc., can also be used.

[0041] (Battery holder 2)

[0042] The battery holder 2 holds a plurality of secondary battery cells 1 . Figure 2 The battery holder 2 holds the plurality of secondary battery cells 1 in a posture parallel to each other in the longitudinal direction and with the end surface electrodes 11 at both ends arranged on the same plane. The battery holder 2 has a box-shaped outer shape and arranges the plurality of secondary battery cells 1 in multiple stages and rows. Figure 6 The battery holder 2 is formed of plastic into a shape having a retaining tube 22 that arranges a plurality of secondary battery cells 1 in a fixed position. The battery holder 2 is a shape in which eight retaining tubes 22 are connected in a parallel posture into four levels and two columns, so that the inner side of the retaining tube 22 is almost equal to the outer shape of the secondary battery cell 1, to serve as a storage space 21. The battery holder 2 in the figure holds eight secondary battery cells 1 in four levels and two columns, so that they are arranged in a posture along the top, bottom, left and right in the figure. The battery holder 2 in the figure arranges eight secondary battery cells 1 in a matrix shape, so that they are in a left-right symmetrical posture when viewed from the front. This structure has the advantage of being able to maintain the battery holder 2 with multiple levels of secondary battery cells 1 in a stable upright posture. The number and arrangement of the secondary battery cells 1 are not limited to this structure, and can also be set to a structure with less than 7 or more than 9 secondary battery cells 1. In addition, it is not limited to four levels and two columns, and various changes can be made to the number of levels and columns. In addition, in addition to being arranged in a matrix shape, it can also be arranged in a staggered shape in an alternating manner in each level. The battery holder 2 is made of a material having excellent insulation and heat resistance, for example, a resin such as polycarbonate or ABS.

[0043] Figure 6 The battery holder 2 is divided into a first holder 2X and a second holder 2Y in the longitudinal direction of the secondary battery cell 1. The battery holder 2 can smoothly insert the elongated secondary battery cell 1.

[0044] The first holder 2X and the second holder 2Y are independently formed by molding plastic and connected to each other by inserting the secondary battery cell 1. The first holder 2X and the second holder 2Y are provided with a cylindrical accommodation space 21 to insert and arrange the cylindrical secondary battery cell 1 at a fixed position.

[0045] The internal shape of the storage space 21 is almost the same as the external shape of the secondary battery cell 1. To be precise, it is slightly larger so that the secondary battery cell 1 can be smoothly inserted and arranged in a fixed position. The first retainer 2X and the second retainer 2Y of this structure are connected to each other at a fixed position via the secondary battery cell 1 when both ends of the cylindrical secondary battery cell 1 are inserted. The first retainer 2X and the second retainer 2Y can be more accurately connected by setting the opposing surfaces as a fitting structure, and are also connected at a fixed position via the non-melting plate 13 described later.

[0046] Figure 2 and Figure 6 The battery assembly 10 shown has a non-melting plate 13 such as a mica plate arranged inside a partition wall 23 arranged between adjacent secondary battery cells 1. The battery holder 2 in the figure arranges the secondary battery cells 1 in 4 levels and 2 rows, so a cross-shaped partition wall 23 is arranged along the top and bottom between the 8 secondary battery cells 1 arranged vertically and horizontally. The partition wall 23 is provided with an insertion gap for inserting the internal non-melting plate 13. The partition wall 23 is inserted into the non-melting plate 13 such as a mica plate in the insertion gap. The battery assembly 10 can prevent the adjacent secondary battery cells 1 from inducing thermal runaway when any one of the secondary battery cells 1 is abnormally heated due to thermal runaway.

[0047] Furthermore, the battery holder 2 is provided with a connection window 24 for exposing the end surface electrode 11 to connect the lead plate 3 at a position opposite to the end surface electrode 11 of the secondary battery cell 1. The connection window 24 for guiding the first electrode 11A as the protruding electrode is set to a size larger than the outer shape of the protruding electrode and capable of inserting the protruding electrode inside. The connection window 24 can arrange the protruding electrode inside and weld it to the lead plate 3, so that the step with the first electrode 11A exposed from the connection window 24 can be reduced, and the lead plate 3 can be welded to the first electrode 11A. The connection window 24 arranged at a position opposite to the second electrode 11B as the bottom surface of the outer can is opened to a size that can guide the welding piece 33 of the lead plate 3 to the second electrode 11B.

[0048] Furthermore, the battery holder 2 is provided with a receiving area 25 for receiving the circuit substrate 4 at an upper portion. Figure 5 The battery holder 2 shown has peripheral walls on the front, rear, left and right sides protruding from the upper surface, and recessed portions are provided inside the peripheral walls on four sides to serve as a storage area 25 for the circuit board 4 . Figure 2 The circuit board 4 is arranged in a gap between the battery holder 2 and the bottom surface of the storage area 25 . Figure 5The circuit board 4 is arranged at a fixed position by setting the outer periphery to fit the inner periphery of the storage area 25. However, the battery holder may be directly fixed to the circuit board installation area by screw fastening or the like, or a substrate holder for holding the circuit board may be separately provided.

[0049] (Lead plate 3)

[0050] The lead plate 3 electrically connects the secondary battery cells 1 held in the battery holder 2. The lead plate 3 is manufactured by stamping a metal plate having excellent conductivity, and is welded and fixed to the end surface electrode 11 provided on the end surface of the secondary battery cell 1 of the battery holder 2. The battery assembly 10 shown in the figure connects eight secondary battery cells 1 in series and in parallel via the lead plate 3. Figure 6 The battery assembly 10 is configured by connecting four secondary battery cells 1 arranged in two rows and four levels in the figure in parallel to each other to form a parallel unit 1X, and connecting the left and right parallel units 1X to each other in series to form a battery block 1Y in which eight secondary battery cells 1 are connected in four parallel connections and two in series. Figure 5 As shown, on the third surface 2C of the box-shaped battery holder 2, the battery assembly 10 connects two sets of parallel units 1X in series via the intermediate lead plate 3B, and as shown in FIG. Figure 5 as well as Figure 7 As shown, in this battery assembly 10 , the output sides of the parallel cells 1X connected in series are connected to the output lead plate 3A on the first surface 2A of the battery holder 2 .

[0051] The output lead plate 3A includes a first output lead plate 3Aa that connects the first electrodes 11A of the plurality of secondary battery cells 1 constituting the parallel unit 1X to each other, and a second output lead plate 3Ab that connects the second electrodes 11B to each other, on the output side of the battery block 1Y. The first output lead plate 3Aa shown in the figure is arranged on the right side of the first surface 2A of the battery holder 2 having a box-shaped outer shape, and is connected to the first electrodes 11A adjacent to each other above and below. The first output lead plate 3Aa shown in the figure is formed in a shape in which a stacking portion 31 and a welding portion 32 are alternately connected. The stacking portion 31 is stacked on the surface of the opening edge of the connection window 24, which is the surface of the battery holder 2. The welding portion 32 is formed in a step shape one step lower than the stacking portion 31 and is connected to the first electrode 11A arranged in the connection window 24. The first output lead plate 3Aa is bent so that the longitudinal cross-sectional shape is substantially rectangular wave-shaped by the stacking portions 31 and the welding portions 32 that are alternately connected. The first output lead plate 3Aa connects the first electrodes 11A of the four secondary battery cells 1, and therefore has four welding portions 32 at the top and bottom, and a stacking portion 31 is provided between and outside these welding portions 32. The first output lead plate 3Aa described above has the stacking portion 31 and the welding portion 32 in a rectangular shape with equal lateral width, and can be simply and easily manufactured by bending a metal plate of the same width.

[0052] The stacked portion 31 is arranged between adjacent first electrodes 11A, and has a lead opening window 30 opened in the center. The first output lead plate 3Aa has lead opening windows 30 opened in the three stacked portions 31 arranged between the four welding portions 32. The lead opening window 30 is set as an opening that allows the discharge discharged from the safety valve of the first electrode 11A of any secondary battery cell 1 to pass through and be discharged to the outside. The stacked portion 31 shown in the figure has an opening in the shape of an elongated circle extending in the second direction, and the second direction intersects with the first line L1 that connects the centers of the first electrodes 11A of adjacent secondary battery cells 1 in the shortest possible manner. The lead opening window 30 can be set to, for example, an elongated circle or an elliptical shape extending in the second direction. When exhaust such as gas is discharged from the safety valve of the first electrode 11A of any secondary battery cell 1, the lead opening window 30 of this shape provided on the first output lead plate 3Aa of the stacked portion 31 can reliably pass the exhaust and discharge it to the outside. This is because, since it is formed to extend in the direction intersecting with the first line L1 connecting the centers of the adjacent first electrodes 11A, that is, the second direction, the exhaust such as gas moving along the first line L1 can be reliably guided to the lead opening window 30. Furthermore, the stacked portion 31 in the figure is provided with a conductive portion 34 of a given width on both sides of the lead opening window 30 opened in the center, thereby obtaining the area of ​​the conduction path lost by providing the lead opening window 30 on the first line L1.

[0053] The welding portion 32 is rectangular in plan view, so that it can contact the first electrode 11A with a larger area. In order to ensure that the welding portion 32 having a rectangular shape in plan view contacts the first electrode 11A exposed from the connection window 24, Figure 8 and Fig. 9 The battery holder 2 shown has a connection window 24 in a substantially rectangular shape when viewed from above, and is formed into an internal shape that can fit the entirety of the welded portion 32. Thus, the first output lead plate 3Aa, which is formed in a flat plate shape to seal the entire surface of the first electrode 11A, also has the advantage that exhaust such as gas exhausted from the safety valve can reliably flow to the laminated portion 31 and be exhausted from the lead opening window 30.

[0054] Furthermore, the plate-shaped welding portion 32 is provided with a slit 32a in the central portion. The welding portion 32 improves the reliability of welding by pressing the welding tool across the slit 32a. The welding portion 32 in the figure is provided with the slit 32a along the first line L1. This structure has the advantage of being able to reliably weld the welding portion to the first electrode 11A by pressing the welding tool with a large area on both sides of the slit 32a. However, the slit may also be provided in a direction intersecting the first line L1.

[0055] Here, one of the focuses of the present invention is described. In the lead plate 3 that connects the adjacent first electrodes 11A to each other, it is necessary to prevent the gas or other exhaust gas discharged from the safety valve of any secondary battery cell 1 from being transmitted through the lead plate 3 and moving to the first electrode 11A of other secondary battery cells 1, thereby causing adverse effects. Fig.11 As shown in the schematic cross-sectional view of FIG. 1 , in a conventional battery pack 90 in which a plurality of secondary battery cells 91 are held by a resin battery holder 92, the battery holder 92 is divided into two, and the secondary battery cells 91 are inserted into the cylinders formed in each of the divided holders, so that the secondary battery cells 91 are held from the left and right. In such a battery pack 90, any one of the secondary battery cells 91 (in Fig.11 In the case of an unsafe event in a secondary battery cell (the upper side in the figure), such as Fig.11 As shown by the arrow, it is considered that high-temperature gas, flame, electrolyte and other discharges released from the safety valve provided in the first electrode 91A of the secondary battery cell 91 are transmitted through the lead plate 93 and move to other adjacent secondary battery cells 91, which may be damaged and burn.

[0056] In contrast, in the battery pack 100 according to the present embodiment, Fig.12 As shown in the figure, as described above, by providing the lead opening window 30 between the adjacent first electrodes 11A in the lead plate 3 facing the first electrode 11A provided with the safety valve, the discharge from the safety valve is made Fig.12 The lead wire opening window 30 is formed with an insulating opening window 53 at a position corresponding to the lead wire opening window 30. Thus, the discharge that has passed through the lead wire opening window 30 can reliably pass through the insulating opening window 53 and be quickly discharged to the outside.

[0057] An intermediate lead plate 3B is arranged over almost the entire surface of the third surface 2C of the battery holder 2, and the intermediate lead plate 3B has a plate-shaped laminated portion 38 connected to the end surface electrodes 11 of the secondary battery cells 1 adjacent to each other in the upper and lower directions and in the left and right directions. The intermediate lead plate 3B connects the secondary battery cells 1 adjacent to each other in parallel via the plate-shaped laminated portion 38 on the third surface 2C of the battery holder 2, and connects the secondary battery cells 1 adjacent to each other in series. The intermediate lead plate 3B has a welding piece 33 welded to the end surface electrode of the secondary battery cell 1 provided on the plate-shaped laminated portion 38. The welding piece 33 is extended with a step relative to the plate-shaped laminated portion 38, and even when there is a height difference between the surface of the battery holder 2 and the surface of the end surface electrode 11, the welding piece 33 is in contact with the surface of the end surface electrode 11 in a surface contact state, thereby improving the reliability of welding. Furthermore, each welding piece 33 is formed with a slit 33a, and the reliability of welding is improved by pressing the welding tool across the slit 33a. The welding piece 33 in the figure divides the welding part into a pair of pieces, and a slit 33a is provided between them, but the welding piece can also be provided with a slender long hole opening as a slit. In the present embodiment, since the adjacent secondary battery cells 1 on the left and right are connected in series with each other, the intermediate lead plate 3B is formed into a flat plate without a step at the position of the plate-like laminated portion 38 connected in series. In addition, in the intermediate lead plate 3B, the space around the welding piece 33 connected to the first electrode 11A of the secondary battery cell 1 becomes a path for discharging the discharge discharged from the safety valve of the first electrode 11A to the outside. In addition, in addition to this discharge path, an opening for discharging the discharge discharged from the safety valve of the first electrode 11A to the outside can also be provided at a position of the intermediate lead plate 3B relative to the upper and lower and / or left and right adjacent secondary battery cells 1.

[0058] Furthermore, the second output lead plate 3Ab is also provided with a welding piece 33 connected to the second electrode 11B in a plate-shaped plate-shaped laminated portion 38 that connects the second electrode 11B of the adjacent secondary battery cell 1. Here, in the second output lead plate 3Ab and the intermediate lead plate 3B, the welding piece 33 connected to the second electrode 11B is connected to the plate-shaped laminated portion 38 via a fusible portion 41 extending in an elongated shape, and when an overcurrent flows, the fusible portion 41 is fused, thereby providing a structure capable of reliably disconnecting the secondary battery cell 1 from the lead plate 3.

[0059] Furthermore, the lead plate 3 is provided with a connection terminal portion 39 protruding upward for connection with the circuit substrate 4. The connection terminal portion 39 led out from the output lead plate 3A is connected to the circuit substrate 4, and the output of the battery block 1Y is supplied to the circuit substrate 4. The connection terminal portion 39 led out from the intermediate lead plate 3B is connected to the circuit substrate 4, and the intermediate voltage of the battery block 1Y is supplied to the circuit substrate 4.

[0060] The lead plate 3 described above can be arranged at a fixed position of the battery holder 2 via a positioning mechanism. Figures 7 to 9 The battery holder 2 shown in the figure has a plurality of positioning ribs 28 protruding from the surface integrally formed in the first surface 2A, and the positioning ribs 28 are used as a positioning mechanism to arrange the lead plate 3 in a fixed position. The lead plate 3 is arranged along the positioning ribs 28 with its outer periphery, so that it is positioned and arranged in a fixed position of the battery holder 2. The welding portion 32 or welding piece 33 of the lead plate 3 arranged in the fixed position is welded to the end surface electrode 11, so that it is fixed in the fixed position. Furthermore, Figures 7 to 9 In the battery holder 2 shown, a part of the positioning rib 28 also functions as a control wall for suppressing the movement of the discharge discharged from the safety valve of the first electrode 11A.

[0061] (Circuit board 4)

[0062] The circuit board 4 is mounted with electronic circuits such as a voltage detection circuit for detecting the total potential and the intermediate potential of the battery block 1Y formed by connecting the secondary battery cells 1 in series and in parallel, a control circuit for controlling charging and discharging, and a protection circuit. The circuit board 4 is formed in a rectangular shape and is arranged in a storage area 25 provided on the upper part of the battery holder 2.

[0063] (Insulation board 5)

[0064] The insulating plate 5 is laminated on the surface of the lead plate 3 fixed in the battery holder 2, and covers the lead plate 3 for insulation. The insulating plate 5 is made of resin or paper, and is preferably an insulating plate that is cheap and easy to handle, and has excellent heat resistance and flame retardancy with respect to the heat of exhaust such as gas discharged from the secondary battery cell 1. As such an insulating plate, for example, aramid paper (Nomex [registered trademark] manufactured by Dupont) can be used. Figure 4The insulating plate 5 shown comprises: a first insulating plate 5A, which is arranged on the first surface 2A of the battery holder 2 having a box-shaped outer shape and covers the output lead plate 3A; a second insulating plate 5B, which is arranged on the third surface 2C of the battery holder 2 and covers the intermediate lead plate 3B; a third insulating plate 5C, which is arranged on the second surface 2B of the battery holder 2 and covers the connection terminal portion 39 of the first output lead plate 3Aa; and a fourth insulating plate 5D, which is arranged on the fourth surface 2D of the battery holder 2 and covers the connection terminal portion 39 of the second output lead plate 3Ab.

[0065] The third insulating plate 5C has a bent piece 51 on one side of the main body portion that covers the connection terminal portion 39 of the first output lead plate 3Aa arranged on the second surface 2B of the battery holder 2, and the bent piece 51 is arranged on the surface of the first output lead plate 3Aa arranged on the first surface 2A of the battery holder 2. The fourth insulating plate 5D has a bent piece 51 on one side of the main body portion that covers the connection terminal portion 39 of the second output lead plate 3Ab arranged on the fourth surface 2D of the battery holder 2, and the bent piece 51 is arranged on the surface of the plate-like laminated portion 38 of the second output lead plate 3Ab arranged on the first surface 2A of the battery holder 2. The first insulating plate 5A has a main body portion that covers the entire first surface 2A of the battery holder 2 on which the third insulating plate 5C and the fourth insulating plate 5D are arranged, and bent pieces 51 connected to both sides of the main body portion, as shown in FIG. Figure 3 As shown, these bent pieces 51 are stacked and arranged on the surfaces of the second insulating plate 5B arranged on the second surface 2B of the battery holder 2 and the fourth insulating plate 5D arranged on the fourth surface 2D. The second insulating plate 5B includes a main body covering the entire third surface 2C of the battery holder 2 and bent pieces 51 connected to both sides of the main body, and these bent pieces 51 are arranged on the surfaces of the second surface 2B and the fourth surface 2D of the battery holder 2.

[0066] The first insulating plate 5A is provided with insulating opening windows 53 at positions corresponding to the lead opening windows 30 provided on the first output lead plate 3Aa, so that the discharge from the safety valve of the first electrode 11A can pass through the insulating opening windows 53 of the insulating plate 5 from the lead opening window 30 and be quickly discharged to the outside. Figure 4The first insulating plate 5A shown is provided with insulating opening windows 53 extending in the vertical direction at three locations in the vertical direction in an area opposite to the three lead opening windows 30 formed on the first output lead plate 3Aa. Each insulating opening window 53 is opened as a slit hole having a total length of about several times the vertical width of the lead opening window 30, so that the discharge discharged to the lead opening window 30 can quickly pass through and be discharged to the outside. The first insulating plate 5A is provided with slit-shaped lead opening windows 30 at three locations in the upper and lower parts on the first line L1 connecting the center of the first electrode 11A. In this way, by providing the insulating opening windows 53 at positions opposite to the lead opening windows 30 provided on the lead plate 3, as shown in FIG. Fig.10 As shown by the arrow, the exhaust such as gas discharged from the safety valve of the first electrode 11A can be quickly guided from the lead opening window 30 to the insulating opening window 53 and discharged to the outside. However, the shape, number, and arrangement of the insulating opening windows 53 provided in the insulating plate 5 are not limited to the above examples, and various changes can be made so that the exhaust flowing into the lead opening window 30 can be quickly discharged to the outside. In addition, the insulating opening window 53 is opened in a slit shape so as not to damage the insulating function of the first insulating plate 5A and the second insulating plate 5B.

[0067] Furthermore, the second insulating plate 5B shown in the figure is provided with an insulating opening window 53 at a position opposite to the first electrode 11A connected via the intermediate lead plate 3B, so that the discharge discharged from the safety valve of the first electrode 11A passes through the insulating opening window 53 of the insulating plate 5 and is discharged to the outside. Figure 4 The second insulating plate 5B shown has slit-shaped insulating opening windows 53 extending in the vertical direction at four locations in the region facing the welding piece 33 of the intermediate lead plate 3B connected to the first electrode 11A.

[0068] The above-described insulating plate 5 can be arranged at a fixed position of the battery holder 2 by means of a fitting structure. Figure 8 as well as Fig. 9 The battery holder 2 shown in the figure has a plurality of positioning protrusions 26 protruding from the surface integrally formed on the first surface 2A and the third surface 2C. The insulating plate 5 is provided with a plurality of positioning holes 56 for inserting the positioning protrusions 26. The insulating plate 5 is arranged at a fixed position of the battery holder 2 in a state where the positioning holes 56 are guided to the positioning protrusions 26, accurately covers the surface of the lead plate, and arranges the insulating opening window 53 at an accurate position.

[0069] (Exterior sheet 7)

[0070] like Figure 1 As shown, the battery assembly 10 in which the insulating plate 5 is arranged on the surface of the lead plate 3 and the surface of the circuit board 4 is covered with the insulating member 6 is covered with the outer cover sheet 7. Figure 3 As shown, the outer sheet 7 is a heat-shrinkable bag or tube, which is heat-shrunk in a state where the battery assembly 10 is contained inside, thereby covering. For such an outer sheet 7, it is preferred to use a resin such as PET that has excellent insulation and stability. In particular, a shrink tube made of PET resin is relatively cheap as a heat shrink tube, so it is preferred. The outer sheet 7 is melted by the high-temperature gas and other exhaust discharged from the safety valve of the first electrode 11A of the secondary battery cell 1, and the exhaust is quickly discharged to the outside of the battery pack 100.

[0071] (Pinout 18, Connector 19)

[0072] Further, Figures 1 to 6 The battery pack 100 shown has a plurality of lead wires 18 connected to the circuit board 4 and led out from the battery assembly 10 to the outside. The lead wires 18 are composed of positive and negative power lines and signal lines, and are directly connected to the connector of the device in which the battery pack 100 is installed. The plurality of lead wires 18 are connected to the circuit board 4 at one end and are connected to the connector 19 at the other end.

[0073] The above battery pack 100 is built into the device body of an electrical device such as a speaker and used as a power source. The battery pack 100 supplies power to the main device via an output wire 18 led out to the outside, or supplies power from the main device to charge the built-in secondary battery cell 1. The output wire 18 led out from the battery pack 100 is connected to the connector on the main body side via an output connector 19 connected to the front end, so that power is supplied.

[0074] Industrial Applicability

[0075] The battery pack according to the present invention can be suitably used as a power source for electric devices such as wireless speakers, electric cleaners, and electric tools, and can also be suitably used in applications such as power supply devices for mobile objects such as power-assisted bicycles and electric carts.

[0076] -Explanation of symbols-

[0077] 100…Battery Pack

[0078] 1…Secondary battery cell

[0079] 1X...Parallel Unit

[0080] 1Y...Battery Block

[0081] 2…Battery holder

[0082] 2X…First retainer

[0083] 2Y…Second retainer

[0084] 2A…Side 1

[0085] 2B…side 2

[0086] 2C…side 3

[0087] 2D…Fourth side

[0088] 3…Lead plate

[0089] 3A...Output lead plate

[0090] 3Aa…First output lead plate

[0091] 3Ab…Second output lead plate

[0092] 3B…Middle lead plate

[0093] 4…Circuit board

[0094] 5…Insulation board

[0095] 5A…First insulating plate

[0096] 5B…Second insulating plate

[0097] 5C…Third insulation board

[0098] 5D…Fourth insulation board

[0099] 6…Insulating components

[0100] 7…Exterior sheet

[0101] 10…Battery assembly

[0102] 11…End electrode

[0103] 11A…First electrode

[0104] 11B…Second electrode

[0105] 13…Non-melting plate

[0106] 18…Pinout

[0107] 19…Connector

[0108] 21…Accommodation space

[0109] 22…Retaining tube

[0110] 23…Partition wall

[0111] 24…Connection window

[0112] 25…Accommodation area

[0113] 26…Positioning convex part

[0114] 28…Positioning ribs

[0115] 30…Lead opening window

[0116] 31…Lamination section

[0117] 32…Welding

[0118] 32a…Slit

[0119] 33…Welding piece

[0120] 33a…Slit

[0121] 34…Conductive part

[0122] 38…Plate-shaped laminated portion

[0123] 39…Connection terminal

[0124] 41…Fuse

[0125] 51…Bending sheet

[0126] 53…Insulated opening window

[0127] 56…Positioning hole

[0128] 90…Battery pack

[0129] 91…Secondary battery cell

[0130] 91A…First electrode

[0131] 92…Battery holder

[0132] 93…Lead plate

[0133] L1…first line.

Claims

1. A battery pack comprising: A plurality of secondary battery cells are provided with end surface electrodes at both ends, at least one of the end surface electrodes is used as a first electrode provided with a safety valve, and are arranged in a posture parallel to the longitudinal direction of each other; a battery holder that holds the plurality of secondary battery cells; a conductive lead plate for connecting the end surface electrodes of adjacent secondary battery cells to each other; and An insulating plate having an insulating property covers the surface of the lead plate, The lead plate has a lead opening window formed between the first electrodes of the adjacent secondary battery cells. The insulating plate forms an insulating opening window at a position corresponding to the lead opening window.

2. The battery pack according to claim 1, wherein: The lead wire opening window extends in a second direction intersecting a first line that shortest connects centers of the first electrodes of adjacent secondary battery cells.

3. The battery pack according to claim 2, The lead plate is provided with conductive parts on both sides of the lead opening window.

4. The battery pack according to claim 1, wherein: The insulating opening window is opened in a slit shape overlapping with the lead wire opening window.

5. The battery pack according to claim 1, wherein: The lead plate includes: a plurality of stacked portions stacked on the surface of the battery holder; and a plurality of welding portions connected between the plurality of stacked portions and connected to the first electrode. The lead opening window is provided in the laminated portion.

6. The battery pack according to claim 5, wherein: The lead plate is formed by bending a metal plate so that the plurality of stacked portions and the plurality of welded portions having steps relative to the stacked portions are alternately provided.

7. The battery pack according to claim 6, wherein: The battery holder is formed into a box shape, and the first electrodes of the plurality of secondary battery cells are arranged on a first surface of the box shape. The battery holder is provided with a connection window on the first surface so as to be open and expose the first electrode. The connection window has an inner shape into which the welding portion of the lead plate can be inserted.

8. The battery pack according to any one of claims 1 to 7, wherein: The battery pack includes a plurality of parallel units, wherein the secondary battery cells are arranged in parallel and connected in parallel. The plurality of parallel units are connected in series to each other to form a battery block in which the plurality of secondary battery cells held by the battery holder are connected in series and in parallel. The lead plate is an output lead plate connected to the output side of the battery block.

9. The battery pack according to any one of claims 1 to 7, wherein: The battery holder is formed into a box shape, and the first electrodes of the plurality of secondary battery cells are arranged on a first surface of the box shape. The battery holder includes a positioning rib on the first surface for placing the outer peripheral edge of the lead plate in contact with the lead plate at a fixed position. The positioning rib also functions as a control wall that suppresses movement of discharge discharged from the safety valve of the first electrode.

10. The battery pack according to any one of claims 1 to 7, wherein: The battery holder is formed into a box shape, and the first electrodes of the plurality of secondary battery cells are arranged on a first surface of the box shape. The battery holder is provided with a positioning protrusion protruding from the surface on the first surface, The insulating plate is formed with a positioning hole for the positioning protrusion to be inserted into, The insulating plate can be positioned on the first surface via the positioning holes and the positioning protrusions.

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