Battery pack

Abstract

To reduce manufacturing costs and prevent the induction of thermal runaway, a battery pack houses a plurality of cylindrical battery cells capable of charge and discharge with a heat-resistant wall (3) disposed therebetween in a mutually parallel attitude in an outer casing. The heat-resistant wall (3) has a heat-insulating recess (4) of an air layer formed in a length (L) extending in a long side direction of the battery cell and a lateral width (W) extending in a circumferential direction on an opposite surface to a surface of the battery cell.

Description

Technical Field

[0001] This invention relates to a battery pack comprising multiple battery cells housed in an outer casing. Background Technology

[0002] As a power source for electrical equipment, battery packs are used, which house multiple battery cells within an external casing. These battery packs connect multiple battery cells in series or parallel to increase capacity. In recent years, there has been a particular demand for high-capacity battery packs, and on the other hand, there is a trend towards higher capacity individual battery cells. Furthermore, structures are being developed that arrange battery cells close to each other without gaps within the battery pack.

[0003] On the other hand, it is extremely difficult to completely eliminate the possibility of thermal runaway caused by internal short circuits, overcharging, and other factors within a battery cell. In a battery pack with multiple battery cells arranged close together, if any battery cell abnormally heats up and experiences thermal runaway, it may release high-temperature gas with significant thermal energy. If the gas released from the thermally runaway battery cell heats adjacent battery cells and induces thermal runaway, it further contributes to the release of large amounts of thermal energy, thus reducing safety. To prevent this adverse effect, the battery pack is required to be designed so that even if any battery cell experiences thermal runaway, it will not induce thermal runaway in adjacent battery cells.

[0004] To prevent the above adverse effects, a battery pack with mica plates arranged between adjacent battery cells has been developed (see Patent Documents 1 and 2).

[0005] Prior art literature

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2012-33464

[0008] Patent Document 2: International Publication No. 2019 / 150772 Summary of the Invention

[0009] -The problem the invention aims to solve-

[0010] The battery packs described in Patent Documents 1 and 2 are configured with mica plates that are in close contact with and curved along the surface of the cylindrical batteries. The battery pack described in Patent Document 1 has curved mica plates on the surfaces of adjacent cylindrical batteries, and further, a heat-resistant plastic wall is placed between the mica plates to prevent thermal runaway. Furthermore, the battery pack described in Patent Document 2 has curved mica plates on the surfaces of adjacent cylindrical batteries, and further, other flat mica plates are placed between opposing mica plates to prevent thermal runaway. These battery packs, in addition to two layers of mica plates between adjacent cylindrical batteries, also have a heat-resistant plastic and mica wall between two mica plates, thus resulting in a complex structure and increased manufacturing cost.

[0011] This invention was developed with the aim of eliminating the above-mentioned disadvantages. One of the objectives of this invention is to provide a battery pack that reduces manufacturing costs and can prevent the induction of thermal runaway.

[0012] -Methods for solving the problem-

[0013] In one aspect of the present invention, a battery pack comprises multiple cylindrical, chargeable and dischargeable battery cells arranged in a parallel configuration with heat-resistant walls between them and housed within an outer casing. The heat-resistant walls have, on their surfaces opposite the battery cell surfaces, heat-insulating recesses forming air layers extending in the long side direction (L) and in the circumferential direction (W) of the battery cell.

[0014] -Invention Effects-

[0015] According to the battery pack of the present invention, a heat-resistant wall with a heat-insulating recess forming an air layer is disposed between the battery cells arranged in a parallel orientation on the surface opposite to the surface of the battery cells. This effectively prevents the induction of thermal runaway by suppressing heat conduction to adjacent battery cells. In particular, the battery pack described above features a simple structure with heat-resistant walls disposed between the battery cells arranged in a parallel orientation, thereby reducing manufacturing costs and effectively preventing the induction of thermal runaway. Attached Figure Description

[0016] Figure 1 This is a perspective view of a battery pack according to one embodiment of the present invention.

[0017] Figure 2 yes Figure 1 The battery pack shown is a cross-sectional view along line II-II.

[0018] Figure 3 yes Figure 1 The image shows an exploded perspective view of the battery pack.

[0019] Figure 4 Viewing from the bottom Figure 1The image shows an exploded perspective view of the battery pack.

[0020] Figure 5 yes Figure 2 An enlarged cross-sectional view of the battery pack shown.

[0021] Figure 6 yes Figure 4 The image shows a bottom view of the battery cell pack.

[0022] Figure 7 It is a schematic perspective view showing the state in which the exhaust flame from the side of the battery cell is discharged to the outside through the heat-insulating recess of the heat-resistant wall.

[0023] Figure 8 This is a schematic perspective view showing the state in which the exhaust flame from the side of the battery cell is discharged to the outside through the inner groove of the heat-resistant wall.

[0024] Figure 9 This is an exploded 3D view of the heat-resistant wall. Detailed Implementation

[0025] One embodiment of the present invention relates to a battery pack consisting of a plurality of cylindrical, chargeable and dischargeable battery cells arranged in a parallel manner with heat-resistant walls between them and housed in an outer casing. The heat-resistant walls have heat-insulating recesses on the surfaces opposite to the battery cells, forming an air layer with a length (L) extending in the long side direction of the battery cells and a lateral width (W) extending in the circumferential direction.

[0026] In other embodiments of the present invention, the heat-insulating recess of the battery pack extends to both ends of the battery cell by a length (L) and has openings at both ends of the battery cell.

[0027] The above-mentioned battery pack allows the high-temperature exhaust gas emitted from the battery cells to the air layer to flow out from the surface of the battery cells to the outside through the heat-insulating recesses, thus preventing thermal failures based on the exhaust gas. The high-temperature exhaust gas stagnating in the air layer between the battery cells and the heat-resistant wall becomes a cause of thermal damage to the heat-resistant wall, and the damage to the heat-resistant wall becomes a cause of thermal runaway.

[0028] In other embodiments of the present invention, the heat-insulating recess of the battery pack is the lateral width (W) of the proximity portion where the outer peripheral surfaces of the battery cells are closest to each other.

[0029] The above battery pack can provide air layers on both sides of the approach portion of the outer peripheral surface of the cylindrical battery cell, so that the exhaust gas ejected from the approach portion and both sides of the battery cell can flow into the air layer to prevent the induction of thermal runaway.

[0030] In other embodiments of the present invention, the battery pack comprises a heat-resistant wall consisting of two heat-resistant plates stacked in the central portion where a heat-insulating recess is provided.

[0031] Because the battery packs described above use two heat-resistant plates stacked together to form a heat-resistant wall, it is possible to efficiently mass-produce heat-resistant walls with complex cross-sectional shapes that can be designed to achieve an ideal profile. This is because the heat-resistant plates can be shaped into various forms and stacked together to create heat-resistant walls with complex cross-sectional shapes.

[0032] In other embodiments of the present invention, the heat-resistant wall of the battery pack is provided with an outer groove, which has an opening disposed on the surface of the battery cell along both sides of the heat-insulating recess.

[0033] Because the battery pack has a heat-insulating recess in the center of the heat-resistant wall and outer grooves on both sides, an air layer based on the heat-insulating recess is formed in the center of the heat-resistant wall, and air layers based on the outer grooves are formed on both sides. Three rows of air layers can be formed on the surface opposite the battery cell. This structure, with its three rows of air layers, provides a wider transverse air layer on the surface of the curved cylindrical battery cell, allowing the exhaust gas from the battery cell to flow into the air layer over a wider area, thus preventing the induction of thermal runaway.

[0034] In other embodiments of the present invention, the heat-resistant plate of the battery pack has a bent sheet formed by bending the two side edges toward the surface of the battery cell, and an outer groove is provided between the bent sheet and the surface of the battery cell.

[0035] Because the above battery pack is formed by bending the two sides of the heat-resistant plate to form a bent sheet, two rows of outer grooves can be provided on the surface of the battery cell, so it can be made into a simple shape, and two rows of outer grooves are provided on both sides of the surface of the battery cell, that is, the heat insulation recess.

[0036] In other embodiments of the present invention, the heat-resistant wall of the battery pack has an inner groove between the two sides of the stacked heat-resistant plates, that is, between the outer grooves on both sides, and the opening is closed by the inner surface of the outer casing.

[0037] The battery pack described above has an inner groove between the valleys formed by arranging the cylindrical battery cells in a parallel orientation. This inner groove can also act as an air layer to insulate adjacent battery cells from heat.

[0038] In other embodiments of the present invention, the heat-resistant plate of the battery pack includes: a first curved portion, a second curved portion, and a third curved portion extending along the long side of the battery cell, wherein the first curved portion, the second curved portion, and the third curved portion are arranged in two rows from the center to both sides. For the heat-resistant plate, a central plane portion is provided between the two rows of first curved portions arranged in the center; upright portions extending from both sides of the central plane portion toward the surface of the battery cell are formed between the first curved portion and the second curved portion; side plane portions are formed between the second curved portion and the third curved portion; a bent piece is formed between the third curved portion and the side edge of the heat-resistant plate; a heat-insulating recess is formed by the central plane portion and the upright portions; an inner groove is formed by the side plane portions and the upright portions; and an outer groove is formed by the side plane portions and the bent piece.

[0039] The above-described battery cell achieves an ideal heat-resistant wall by bending and stacking two heat-resistant plates. Specifically, the battery pack stacks two heat-resistant plates, forming a heat-insulating recess in the center of both sides, outer grooves on both sides of the heat-insulating recess, and further forming an inner groove between the outer grooves on both sides of the heat-resistant wall. By creating an air layer between the heat-insulating recess, outer grooves, and inner groove, adjacent battery cells can be insulated. Therefore, it has the following advantages: the heat-resistant wall is shaped ideally for preventing thermal runaway; and by stacking two heat-resistant plates, manufacturing costs can be reduced and mass production can be carried out efficiently.

[0040] Other embodiments of the present invention involve battery packs in which the heat-resistant plate is made of inorganic material.

[0041] The battery pack features heat-resistant walls with excellent heat resistance, effectively preventing thermal damage to the heat-resistant plates caused by exhaust gases emitted from the battery cells.

[0042] In other embodiments of the present invention, the inorganic material plate of the battery pack is a bent mica plate, which is joined together in a stacked state at the central part.

[0043] Since the above battery pack is made of mica sheet with heat-resistant plate bent, the heat-resistant wall has excellent heat resistance properties. By bending and stacking the mica sheet, the heat-resistant wall can be made into an ideal shape and can be mass-produced efficiently.

[0044] In other embodiments of the present invention, the heat-resistant wall of the battery pack includes two mica plates that are bent in the first, second, and third bends, and the mica plates are joined in a stacked state at the central plane.

[0045] The above-mentioned battery pack uses bent mica sheets stacked in the central part to form a heat-resistant wall. Therefore, in the area closest to the cylindrical battery cells, two mica sheets with excellent heat resistance are stacked as two layers, achieving even better heat resistance. Furthermore, since outer grooves are formed on both sides of the central part by the bent mica sheets, the heat-resistant wall can be configured with three rows of air layers on the opposing surfaces of adjacent battery cells, including air layers based on heat-insulating recesses and air layers based on the outer grooves, which have particularly excellent heat resistance. The three rows of air layers are configured with a wider area on the opposing surfaces of the battery cells, effectively guiding the exhaust gas from the battery cells towards the air layers, further preventing the induction of thermal runaway.

[0046] In other embodiments of the present invention, the lateral width (W) of the heat-insulating recess of the battery pack is more than 15% of the outer diameter of the battery cell.

[0047] In other embodiments of the present invention, the lateral width (W) of the heat-insulating recess of the battery pack is less than 60% of the outer diameter of the battery cell.

[0048] In other embodiments of the present invention, the minimum gap (d) between the heat-resistant wall at the heat-insulating recess of the battery pack and the surface of the battery cell is 5 mm or less.

[0049] Other embodiments of the present invention include a battery pack comprising: a temperature sensor for detecting the temperature of the battery cell, the temperature sensor being disposed between a heat-resistant wall and the surface of the battery cell.

[0050] The above battery packs have temperature sensors thermally coupled to the surface of the battery cells, which enables them to quickly detect the temperature of the battery cells with high accuracy.

[0051] Other embodiments of the present invention include a battery pack comprising: a temperature sensor for detecting the temperature of the battery cells, the temperature sensor being disposed in an outer slot.

[0052] The above battery pack has a temperature sensor installed in the outer slot of the heat-resistant wall, thus having the following characteristics: the temperature sensor can be easily positioned in an ideal location, and the temperature sensor can detect the temperature of the battery cell with higher accuracy.

[0053] Other embodiments of the present invention include a battery pack comprising: a voltage detection line connected to the end face electrode of the battery cell and detecting the voltage of the battery cell, the voltage detection line being disposed in an outer slot.

[0054] The above battery pack has voltage detection lines arranged in the outer slot of the heat-resistant wall, thus having the following characteristics: the voltage detection lines can be arranged in a fixed position in a space-saving manner, and the voltage of the battery cells can be detected.

[0055] In other embodiments of the present invention, the outer casing of the battery pack includes: a surface plate portion disposed on the same plane as the surfaces of a plurality of battery cells arranged in a parallel orientation; the surface plate portion having a positioning rib protruding toward the inner surface side; the positioning rib is guided toward the inner groove to position the heat-resistant wall in a fixed position of the outer casing.

[0056] The battery pack described above has the feature of positioning the heat-resistant wall in a fixed position within the outer casing and being able to be configured by guiding the positioning ribs provided on the surface plate of the outer casing towards the inner groove of the heat-resistant wall.

[0057] The embodiments of the present invention will now be described based on the accompanying drawings. These embodiments are examples used to embody the technical concept of the present invention, and the present invention is not limited to these embodiments. Furthermore, this specification does not define the components shown in the claims as components of the embodiments. In particular, the dimensions, materials, shapes, and relative arrangements of the structural components described in the embodiments are not intended to limit the scope of the present invention unless specifically stated otherwise; they are merely illustrative examples. Additionally, the sizes and positional relationships of the components shown in the accompanying drawings may be exaggerated for clarity. Furthermore, in the following description, detailed descriptions of the same names and symbols representing the same or similar components are appropriately omitted. Furthermore, the elements constituting the present invention may also be configured such that multiple elements are constituted by the same components and one component serves as multiple elements, or conversely, multiple components may be used to share the function of one component. Moreover, the content described in some embodiments and implementations can be applied to other embodiments and implementations.

[0058] (Implementation Method 1)

[0059] Figures 1 to 6 The text indicates a battery pack according to an embodiment of the present invention. Figure 1 A 3D view showing battery pack 100. Figure 2 express Figure 1 A cross-sectional view of the battery pack 100 at line II-II. Figure 3 express Figure 1 Exploded perspective view of battery pack 100 Figure 4 Indicates viewing from the bottom side Figure 1 Exploded perspective view of battery pack 100 Figure 5 express Figure 2 Enlarged cross-sectional view of battery pack 100 Figure 6 This is a bottom view of the battery cell pack 10, which connects the battery block 9 to the circuit board.

[0060] The battery pack 100 internally houses multiple chargeable and dischargeable battery cells 1, which are connected in series or parallel to obtain capacity and can be charged and discharged. The battery pack 100 is connected to an external device that drives the device, and power is provided by discharging the battery cells 1. Here, an example of a laptop computer being used as the external device connected to the battery pack 100 is shown; however, the battery pack of the present invention does not limit the connected external device to a laptop computer, and can also be used with other electronic devices, electrical devices, such as mobile phones, portable DVD players, portable car navigation systems, portable music players, power tools, or bicycles. Furthermore, the battery pack can be used either by directly attaching it to an external device, or by housing it inside the external device, or by connecting it via cables.

[0061] Figures 1 to 5 The battery pack 100 shown includes: a plurality of cylindrical, chargeable and dischargeable battery cells 1; an outer casing 2 housing the plurality of battery cells 1; and heat-resistant walls 3 disposed between adjacent battery cells 1. The battery pack 100 arranges the plurality of battery cells 1 in a parallel orientation, with the heat-resistant walls 3 disposed between them and housed within the outer casing 2. The heat-resistant walls 3 have heat-insulating recesses 4 on their surfaces opposite the surfaces of the battery cells 1, forming an air layer with a length (L) extending in the long side direction of the battery cell 1 and a lateral width (W) extending in the circumferential direction. The battery pack 100 is configured to prevent the induction of thermal runaway to adjacent battery cells 1 by means of the heat-resistant walls 3 disposed between the battery cells 1.

[0062] (Outer casing 2)

[0063] like Figure 1 As shown, the battery pack 100 is formed into a box shape that is approximately quadrangular in top view. The main body of the box shape is composed of an outer casing 2. Figure 3 and Figure 4 As shown, the outer casing 2 is divided into a lower casing 2A and an upper casing 2B. The outer casing 2 includes a connector 14 for connecting to an electrical device (in this case, a notebook computer) powered by the battery pack 100. Furthermore, the outer casing 2 may also be provided with a connection mechanism for connecting the battery pack 100 to the electrical device and a locking mechanism for maintaining the assembled state. The outer casing 2 is made of a material with excellent insulation and heat insulation properties, such as a resin like polycarbonate.

[0064] like Figures 2 to 5As shown, inside the outer casing 2, multiple battery cells 1, heat-resistant walls 3 disposed between the battery cells 1, and a circuit board 8 are housed. The battery pack 100 shown in the figure has multiple battery cells 1 arranged in a parallel orientation with heat-resistant walls 3 disposed between them. The end face electrodes at both ends of the battery cells 1 are connected to lead plates 11 to form battery blocks 9, and the lead plates 11 of the battery blocks 9 are connected to the circuit board 8, serving as the core package 10 of the battery connected to the circuit board 8 and housed in the outer casing 2.

[0065] (Battery Unit 1)

[0066] Battery cell 1 is a lithium-ion rechargeable battery. However, battery cell 1 can be a non-aqueous electrolyte rechargeable battery other than a lithium-ion rechargeable battery. In addition, battery cell 1 can use rechargeable rechargeable batteries such as nickel-metal hydride batteries and nickel-cadmium batteries, especially batteries that generate heat at high temperatures during use. Battery cell 1 uses a cylindrical battery with a cylindrical outer casing.

[0067] like Figure 6 As shown, multiple battery cells 1 are configured in a parallel orientation and constitute a battery block 9. The battery block 9 in the attached figure is configured with six cylindrical battery cells 1 arranged in six columns. This battery block 9 is configured as a battery pack 1X in which two battery cells 1 are arranged side-by-side in the same direction and connected at their end faces by a lead plate 11, and three battery packs 1X are arranged alternately in opposite directions and connected at their end faces by lead plates 11, thus connecting adjacent battery packs 1X in series. The six battery cells 1 are connected in two parallel and three series configurations. While the battery block 9 in the attached figure connects six battery cells 1 in two parallel and three series configurations, the number of battery cells 1 and the connection method can be freely changed.

[0068] Multiple battery cells 1 are connected in series and parallel via lead plates 11. Lead plates 11 are constructed by bending a metal plate with excellent conductivity. Lead plates 11 are welded to and connected to the end electrodes of battery cells 1. Furthermore, the positive and negative outputs of the battery block 9 are connected to the circuit board 8 via output leads 11a and 11b. The circuit board 8 houses charging / discharging circuits and protection circuits. In order to monitor the voltage of each battery cell 1, the circuit board 8 connects to the intermediate potential measurement leads 11c and 11d provided on the lead plates 11 directly or via voltage detection lines 12, and connects to temperature sensors 13 for detecting the temperature of each battery cell 1. Thermistors or similar devices are used in the temperature sensors 13. The circuit board 8 in the attached figure has connectors 14 directly connected to the board, allowing these connectors 14 to protrude from the opening 2b of the outer casing 2 and connect to external devices.

[0069] (Heat-resistant wall 3)

[0070] A heat-resistant wall 3 is disposed between the battery cells 1 to suppress heat conduction between adjacent battery cells 1 and to prevent exhaust gases ejected from the sides of a thermally runaway battery cell 1 from adversely affecting adjacent battery cells 1. In a cylindrical battery cell 1, during thermal runaway, not only is there exhaust from the gas valves located on the end faces, but exhaust gases may also be ejected from cracks on the sides of the battery cell 1. In a battery pack with multiple battery cells 1 arranged in a parallel orientation, it is important to prevent the induction of thermal runaway due to exhaust gases ejected from cracks on the sides of the battery cells 1 during thermal runaway. In the battery pack of the present invention, these adverse effects are eliminated by disposing of heat-resistant walls 3 with a unique shape between adjacent battery cells 1.

[0071] The heat-resistant wall 3 is made of a material with excellent insulation and heat resistance. Preferably, the heat-resistant wall 3 is made of an inorganic material, such as mica. Mica has high flame retardancy and non-combustibility, excellent insulation, and a relatively low price, making it suitable as a component requiring both heat resistance and insulation. The heat-resistant wall 3, with its excellent heat resistance, will not burn or melt even from the high-temperature exhaust gases or flames ejected from the battery cell 1, preventing the exhaust gases or flames from penetrating the heat-resistant wall and reaching adjacent battery cells 1. Furthermore, to suppress heat conduction to adjacent battery cells 1, the heat-resistant wall 3 has heat-insulating recesses 4 on both sides of the central portion of the surface opposite to the battery cell 1, forming an air layer with a length (L) extending in the long side direction of the battery cell 1 and a lateral width (W) extending in the circumferential direction. The heat-resistant wall 3, disposed between the battery cells 1, forms two air layers between adjacent battery cells 1 through the heat-insulating recesses 4, thereby suppressing heat conduction between adjacent battery cells 1.

[0072] Furthermore, the heat-insulating recess 4 also functions as a discharge path for directing the flow of high-temperature exhaust gases, flames, etc., ejected from the side of the battery cell 1 in a specific direction. If an exhaust flame is generated due to an anomaly in the battery cell 1, the direction of the flame flow is difficult to predict. If other battery cells 1 are located ahead of this flow, thermal runaway may propagate due to propagation and burning. Therefore, by intentionally providing a discharge path, even if an exhaust flame occurs, undesirable runaway of the battery cell 1 can be suppressed, and the flame flow can be controlled. That is, by utilizing the heat-resistant wall 3 to provide a discharge path within the battery pack 100, even in the event of an exhaust flame, a structure can be designed to direct the exhaust flame in a predetermined direction. Figure 7 The heat-insulating recess 4 shown is designed to extend to both ends of the battery cell 1 by a length (L), and opens at both ends of the battery cell 1. Thus, by designing the heat-insulating recess 4 to extend to both ends of the battery cell 1 by a length (L), and opening at both ends, it is possible to... Figure 5As shown by arrow A, the high-temperature exhaust gas and flames discharged from the side of battery cell 1 into the air layer of the heat insulation recess 4 are like... Figure 7 As shown by the arrow, the gas flows out from the surface of the battery cell 1 through the heat insulation recess 4, thereby controlling the flow of exhaust gas and flame, which can effectively prevent the induction of thermal runaway.

[0073] Figure 5 The heat-insulating recess 4 shown is defined with a lateral width (W) such that, in cross-section, the outer peripheral surfaces of the next pair of battery cells 1 include the closest approach portions 1a. When the heat-resistant wall 3 is positioned between adjacent battery cells 1, it reliably guides the closest approach portions 1a towards the heat-insulating recess 4, preventing adjacent battery cells 1 from conducting heat to each other over the shortest distance. Furthermore, by setting the lateral width (W) of the heat-insulating recess 4 to include the width of the approach portions 1a of the battery cells 1, air layers can also be provided on both sides of the approach portions 1a. When cracks occur in the approach portions 1a and their sides of the battery cells 1, the ejected exhaust gas and flame can reliably flow into the heat-insulating recess 4, thus limiting their exhaust direction.

[0074] The lateral width (W) of the heat insulation recess 4 is 15% or more of the outer diameter (D) of the battery cell 1, preferably 20% or more, and more preferably 25% or more. Furthermore, the lateral width (W) of the heat insulation recess 4 is 60% or less of the outer diameter (D) of the battery cell 1, preferably 50% or less, and more preferably 40% or less.

[0075] (Heat-resistant plate 30)

[0076] like Figure 9 As shown, Figure 5 The heat-resistant wall 3 is formed by stacking two heat-resistant plates 30. The two heat-resistant plates 30 are joined together in the center and heat-insulating recesses 4 are provided on both sides. The heat-resistant plate 30 is a plate that does not deform at the temperature of the abnormally heated battery cell 1, and preferably is an inorganic plate such as a mica plate. For inorganic plates, it is also possible to replace the mica plate by using parts that are sintered or formed in the form of inorganic powder plates, or parts that are plate-shaped inorganic materials or parts formed in the form of inorganic fiber plates.

[0077] like Figure 5As shown, the heat-resistant wall 3, formed by two heat-resistant plates 30, has outer grooves 5 along both sides of the heat-insulating recess 4, with openings disposed on the surface of the battery cell 1. The heat-resistant plates 30 shown in the figure are bent at both sides towards the surface of the battery cell 1, and bent pieces 37 are provided. The outer grooves 5 are provided between the bent pieces 37 and the surface of the battery cell 1. By bending the two sides of the heat-resistant plate 30 to form the bent pieces 37, the heat-resistant wall 3 can provide two rows of outer grooves 5 on both sides of the heat-insulating recess 4 on the surface of the battery cell 1. Since the heat-insulating recess 4 is provided in the center of the heat-resistant wall 3, and the outer grooves 5 are provided on both sides, an air layer based on the heat-insulating recess 4 can be provided in the center of the heat-resistant wall 3, air layers based on the outer grooves 5 can be provided on both sides, and three rows of air layers can be provided on the surface opposite to the battery cell 1. This structure uses three rows of air layers to create a wider horizontal air layer on the surface of the curved cylindrical battery cell 1. The high-temperature exhaust gas and flame emitted from the battery cell 1 flow into the air layer over a wider area, which can prevent the induction of thermal runaway.

[0078] Furthermore, the heat-resistant wall 3 is constructed by providing bent pieces 37 on both sides of the heat-resistant plate 30, such as... Figure 5 As shown, the upper and lower ends of the heat-resistant wall 3 can approach or contact the inner surface of the outer casing 2 with a relatively wide area. According to this structure, the surface distance along which the high-temperature exhaust gas and flame ejected from the thermally runaway battery cell 1 flows towards the adjacent battery cell 1 can be increased. Therefore, it is possible to effectively prevent the high-temperature exhaust gas and flame ejected from the battery cell 1 from passing between the heat-resistant wall 3 and the outer casing 2 and reaching the adjacent battery cell 1.

[0079] Furthermore, such as Figure 5 and Figure 6 As shown, the heat-resistant wall 3 utilizes the outer groove 5 as a storage space for the temperature sensor 13. This structure effectively prevents the temperature sensor 13, disposed in the outer groove 5, from floating up and detaching from the surface of the battery cell 1. Therefore, instead of fixing the temperature sensor to the battery cell surface in a thermally coupled state via a thermally conductive adhesive as in the past, the temperature sensor 13 can be guided from the front end of the bending piece 37 towards the outer groove 5, allowing for simple placement in a fixed position and accurate temperature detection. The temperature sensor 13, guided by the outer groove 5, is as follows... Figure 5 as well as Figure 6 As shown by the dashed lines, in the area housing the temperature sensor 13, it is held in a fixed position by attaching fixing tape 15 to adjacent battery cells 1. Further, as... Figure 6As shown, the outer groove 5 of the heat-resistant wall 3 can also be configured as a storage space for the voltage detection line 12. Here, although the heat-resistant wall 3 increases the surface distance by lengthening the bending piece 37, if the bending piece 37 is too long, it becomes difficult to bend the heat-resistant plate 30, and the gap between the front end of the bending piece 37 and the surface of the battery cell 1 narrows, making it difficult to smoothly insert the temperature sensor 13, voltage detection line 12, etc. Therefore, the length of the bending piece 37 of the heat-resistant wall 3 is determined considering these factors, so that a gap of 1 mm or more, preferably 2 mm or more, is formed between the front edge of the bending piece 37 and the surface of the battery cell 1.

[0080] Furthermore, the heat-resistant wall 3 has an inner groove 6 between the two sides of the stacked heat-resistant plate 30, that is, between the outer grooves 5 on both sides. Figure 5 The heat-resistant wall 3 shown has an inner groove 6 formed between the valleys, allowing the battery cell 1, bent into a cylindrical shape, to be configured in a parallel orientation. This inner groove 6 is as follows... Figure 2 As shown, with the battery cell pack 10 housed within the outer casing 2, the opening on the inner surface of the outer casing 2 is closed, and the space between the inner groove 6 and the outer casing 2 serves as an air layer, enabling heat insulation between adjacent battery cells 1. Specifically, in the region between the valleys of adjacent battery cells 1, by providing an air layer consisting of three rows of air layers—one based on the outer groove 5 formed on the surface of each battery cell 1 and the other based on the inner groove 6 formed between the left and right outer grooves 5—an excellent heat insulation structure can be achieved.

[0081] Furthermore, the inner groove 6 also functions as a discharge path for directing the high-temperature exhaust gas, flame, etc., ejected from the side of the battery cell 1 in a specific direction. The inner groove 6 positioned at this location is as follows... Figure 5 As shown by arrows A and B, when a crack appears on the side of battery cell 1, resulting in the emission of high-temperature exhaust gas and flames, as... Figure 5 As shown by arrow C, the high-temperature exhaust gas and flame flowing towards the adjacent battery cell 1 will not pass through the bending plate 37 on the opposite side, even if they pass through the bending plate 37 near the front side. Figure 8 As indicated by the arrow, the inner groove 6 serves as the discharge path to the outside. That is, the exhaust gas and flame injected from the side of the battery cell 1 and passing through the bending piece 37 near the front side flow in a specific direction via the inner groove 6, thereby controlling the flow of exhaust gas and flame and effectively preventing the induction of thermal runaway to adjacent battery cells 1.

[0082] like Figure 5 and Figure 9As shown, the heat-resistant wall 3 described above is formed by bending a heat-resistant plate 30, which is an inorganic material, into a predetermined shape, and by stacking and joining two heat-resistant plates 30 at the central portion to form a predetermined cross-sectional shape. This structure, which stacks two heat-resistant plates 30 to form the heat-resistant wall 3, allows for efficient mass production of heat-resistant walls 3 with complex cross-sectional shapes, where each heat-resistant plate 30 is shaped into various forms and ideal shapes. In particular, by stacking and joining heat-resistant plates 30 of the same shape, it is possible to efficiently mass-produce heat-resistant walls 3 with symmetrical cross-sectional shapes, reducing manufacturing costs. Here, depending on the type of inorganic material, it is also possible to heat / compress inorganic materials with resin, adhesives, etc., together through a mold frame or the like to form a predetermined shape; however, in this specification, such forming also includes bending processes.

[0083] Figure 5 and Figure 9 Each heat-resistant plate 30 constituting the heat-resistant wall 3 shown has: a first curved portion 31, a second curved portion 32, and a third curved portion 33 extending in the long side direction of the battery cell 1, and the first curved portion 31, the second curved portion 32, and the third curved portion 33 are arranged in two rows from the center to both sides. Further, the heat-resistant plate 30 has a central flat portion 34 between the two rows of first curved portions 31 arranged in the center, an upright portion 35 extending from both sides of the central flat portion 34 toward the surface of the battery cell 1 between the first curved portion 31 and the second curved portion 32, two side flat portions 36 between the second curved portion 32 and the third curved portion 33, and a bent piece 37 between the third curved portion 33 and the side edge of the heat-resistant plate 30. The heat-resistant plate 30 in the attached figure forms a heat-insulating recess 4 through a central flat portion 34 and two raised portions 35 on both sides, an inner groove 6 through two flat portions 36 and raised portions 35, and an outer groove 5 through two flat portions 36 and bent pieces 37.

[0084] The heat-insulating recess 4, formed by the central plane portion 34 and the raised portions 35 on both sides, creates an air layer between the central plane portion 34 and the battery cell 1. The lateral width (W) and depth of the heat-insulating recess 4 are determined such that an air layer is formed between the surface of the battery cell 1 disposed therein and the central plane portion 34. The heat-insulating recess 4 is formed such that the minimum gap (d) between the surface of the battery cell 1 and the central plane portion 34 is 5 mm or less. Further, the heat-insulating recess 4 is preferably formed such that the approach portion of the surface of the battery cell 1 is separated from the central plane portion 34, creating a gap. The lateral width (W) and depth of the heat-insulating recess 4 are determined such that a minimum gap (d) of 0.5 mm or more, preferably 1 mm or more, is formed between the approach portion of the surface of the battery cell 1 and the central plane portion 34. The opening of the heat-insulating recess 4 is closed by the surface of the battery cell 1 disposed therein. Figure 5The heat-resistant plate 30 shown has a chamfered edge on the battery cell 1 side of the second bend 32, and the contact portion with the battery cell 1 is made into an inclined surface, so that the second bend 32 can contact the surface of the battery cell 1 with a wider area. Furthermore, Figure 5 The first curved portion 31 shown provides upright portions 35 by bending the heat-resistant plate 30 at obtuse angles at both ends of the central plane portion 34. However, the first curved portion can also bend the heat-resistant plate 30 at right angles or acute angles.

[0085] Figure 9 The heat-resistant wall 3 shown comprises two mica plates 30A that have been bent at a first bend 31, a second bend 32, and a third bend 33. The two mica plates 30A are joined in a stacked state at a central plane 34. The two mica plates 30A joined at the central plane 34 form heat-insulating recesses 4 on both sides. In the central region closest to the cylindrical battery cell 1, the two mica plates 30A, with their excellent heat resistance, are stacked in two layers, achieving even better heat resistance. The two mica plates 30A are joined at opposite central planes 34 by an adhesive. For example, an epoxy-based adhesive can be used as such an adhesive.

[0086] (Circuit board 8)

[0087] The circuit board 8 is designed to be L-shaped when viewed from above, and is arranged along two sides of the rectangular battery block 9 when viewed from above, and along two sides of the periphery of the box-shaped outer casing 2. The L-shaped circuit board 8 has a first region 8A and a second region 8B connected at right angles. The first region 8A is arranged along one side of the battery block 9, that is, the side of the cylindrical battery cell 1. The second region 8B is arranged opposite to one end face of the battery block 9, that is, one end face of the plurality of cylindrical battery cells 1. In the circuit board 8 shown in the figure, the connector 14 for external connection is fixed in the first region 8A, and in the second region 8B, the connecting lead portion 11c for detecting the voltage of each battery pack 1X and the voltage detection line 12 connected to the connecting lead portion 11d are connected, and the temperature sensor 13 for detecting the temperature of each battery cell 1 is also connected. Furthermore, at one end of the first region 8A of the L-shaped circuit board 8, an output lead portion 11a of the lead plate 11 connected to the battery block 9 is connected, and at one end of the second region 8B of the L-shaped circuit board 8, another output lead portion 11b of the lead plate 11 connected to the battery block 9 is connected.

[0088] (Positioning rib)

[0089] Furthermore, Figures 2 to 5The outer casing 2 shown has a surface plate portion 2a disposed on the same plane as the surfaces of a plurality of battery cells 1 arranged in a parallel posture. On the inner surface side of the surface plate portion 2a, a positioning rib 16 is provided for positioning the heat-resistant wall 3 of the battery core pack 10 housed in the outer casing 2 in a fixed position. Figure 3 as well as Figure 4 The positioning ribs 16 shown are a pair of parallel ribs 16A formed in a mutually parallel posture. The pair of parallel ribs 16A are spaced apart to guide into the inner groove 6. By inserting the pair of parallel ribs 16A into the inner groove 6, the heat-resistant wall 3 can be positioned and configured in a fixed position on the inner surface of the outer casing 2. For example, the spacing of the pair of parallel ribs 16A can be adjusted so that they are pressed in along the inner surface of the inner groove 6, thereby fixing the heat-resistant wall 3 so that it does not shift relative to the outer casing 2 while the pair of parallel ribs 16A are embedded in the inner groove 6. However, the pair of parallel ribs 16A can also be spaced apart to allow smooth insertion into the inner surface of the inner groove 6.

[0090] like Figure 4 As shown, the positioning rib 16 formed on the inner surface of the upper housing 2B has a total length almost equal to that of the heat-resistant wall 3, and is configured to be inserted almost entirely into the inner groove 6 formed on the upper part of the heat-resistant wall 3. Thus, the configuration of connecting the heat-resistant wall 3 via the positioning rib 16 inserted almost entirely into the inner groove 6 reliably prevents high-temperature exhaust gases and flames ejected from the battery cell 1 from passing between the heat-resistant wall 3 and the outer housing 2. Furthermore, the positioning rib 16 formed on the inner surface of the lower housing 2A is as follows... Figure 3 As shown, it is set to be connected to a portion of the heat-resistant wall 3 along its entire length. In this way, the positioning rib 16 that connects to the portion of the heat-resistant wall 3 is positioned in a location that does not affect the fixing tape 15 attached to the surface of the battery cell 1.

[0091] Industrial availability

[0092] The battery pack involved in this invention can be appropriately used as a rechargeable battery pack for battery-powered devices such as notebook computers, mobile phones, portable DVD players, portable car navigation systems, portable music players, power tools, and electric bicycles.

[0093] -Symbol Explanation-

[0094] 100... battery pack

[0095] 1... Battery unit

[0096] 1a...Approaching section

[0097] 1X... Battery Pack

[0098] 2...External casing

[0099] 2A...Lower housing

[0100] 2B... Upper shell

[0101] 2a... Surface plate section

[0102] 2b...Opening window

[0103] 3...Heat-resistant wall

[0104] 4...Thermal insulation recess

[0105] 5...Outer groove

[0106] 6...Inner groove

[0107] 8...Circuit board

[0108] 8A... Area 1

[0109] 8B...Region 2

[0110] 9... Battery Block

[0111] 10...core package

[0112] 11...leadboard

[0113] 11a, 11b... Output lead section

[0114] 11c, 11d... connecting lead section

[0115] 12...Voltage detection line

[0116] 13...Temperature sensor

[0117] 14... Connector

[0118] 15... Fixing tape

[0119] 16... Positioning Rib

[0120] 16A... Parallel Ribs

[0121] 30... Heat-resistant board

[0122] 30A...mica board

[0123] 31...First bend

[0124] 32...Second bend

[0125] 33... Third bend

[0126] 34...Central Plane Section

[0127] 35...Erecting section

[0128] 36...Both sides of the flat surface

[0129] 37... Bending sheet.

Claims

1. A battery pack comprising multiple cylindrical, chargeable and dischargeable battery cells arranged in a parallel configuration with heat-resistant walls between them, and housed within an outer casing. The heat-resistant wall has a heat-insulating recess on its surface opposite to the battery cell surface, forming an air layer with a length (L) extending in the long side direction of the battery cell and a lateral width (W) extending in the circumferential direction. The heat-resistant wall comprises two heat-resistant plates stacked in the central part where the heat-insulating recess is provided. The heat-resistant wall includes: an outer groove, with openings disposed on the surface of the battery cell along both sides of the heat-insulating recess. The heat-resistant plate has bent tabs formed by bending both side edges toward the surface of the battery cell, and the outer groove is provided between the bent tabs and the surface of the battery cell. The heat-resistant wall has an inner groove between the two sides of the stacked heat-resistant plates, i.e., between the outer grooves on both sides, which is closed by the inner surface of the outer casing.

2. The battery pack according to claim 1, wherein, The heat-insulating recess is a length (L) extending to both ends of the battery cell, with openings at both ends of the battery cell.

3. The battery pack according to claim 1 or 2, wherein, The heat insulation recess is the lateral width (W) of the proximity portion where the outer peripheral surfaces of the battery cells are closest to each other.

4. The battery pack according to claim 1, wherein, The heat-resistant plate has: a first curved portion, a second curved portion, and a third curved portion extending along the long side of the battery cell. The first curved portion, the second curved portion, and the third curved portion are arranged in two rows from the center outwards to both sides. The heat-resistant plate: A central plane portion will be provided between the first curved portions, which are arranged in two columns in the central portion. A raised portion extending from both sides of the central plane portion toward the surface of the battery cell is formed between the first curved portion and the second curved portion. A two-sided planar portion is formed between the second curved portion and the third curved portion. The bending piece is formed between the third bent portion and the side edge of the heat-resistant plate. The heat-insulating recess is formed by the central plane portion and the raised portion. The inner groove is formed by the two flat portions on both sides and the raised portion. The outer groove is formed by the two side planar portions and the bent piece.

5. The battery pack according to claim 1 or 4, wherein, The heat-resistant board is an inorganic board.

6. The battery pack according to claim 5, wherein, The inorganic board is a mica board that has been bent and processed, and the mica board is joined together in a stacked state at the central part.

7. The battery pack according to claim 4, wherein, The heat-resistant wall comprises two mica plates that have been bent in the first, second, and third bends. The mica panels are joined together in a stacked manner at the central plane.

8. The battery pack according to claim 1 or 2, wherein, The lateral width (W) of the heat insulation recess is more than 15% of the outer diameter of the battery cell.

9. The battery pack according to claim 1 or 2, wherein, The lateral width (W) of the heat insulation recess is less than 60% of the outer diameter of the battery cell.

10. The battery pack according to claim 1 or 2, wherein, The minimum gap (d) between the heat-resistant wall at the heat-insulating recess and the surface of the battery cell is less than 5 mm.

11. The battery pack according to claim 1 or 2, wherein, The battery pack includes a temperature sensor to detect the temperature of the battery cells. The temperature sensor is disposed between the heat-resistant wall and the surface of the battery cell.

12. The battery pack according to any one of claims 1, 4, and 7, wherein, The battery pack includes a temperature sensor to detect the temperature of the battery cells. The temperature sensor is configured in the outer slot.

13. The battery pack according to any one of claims 1, 4, and 7, wherein, The battery pack includes: a voltage detection line connected to the end electrode of the battery cell to detect the voltage of the battery cell. The voltage detection line is positioned in the outer slot.

14. The battery pack according to any one of claims 1, 4, and 7, wherein, The outer casing includes a surface plate portion disposed on the same plane as the surfaces of the plurality of battery cells arranged in a parallel orientation. The surface plate portion has positioning ribs that protrude toward the inner surface side, and the positioning ribs are guided toward the inner groove to position the heat-resistant wall in the fixed position of the outer housing.

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