JP2018037181A - Battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the spread of heat to the surroundings due to ignition of one or more battery cells in a battery module having a plurality of cylindrical batteries in close proximity inside a case. A battery module (10) includes a plurality of tubular batteries (12) and a protective case (16) that houses the plurality of tubular batteries (12) in close proximity to each other. An inlet opening 34 through which air for cooling the cylindrical battery 12 flows into the protective case 16 is formed in one side wall 17a of the protective case 16, and an outlet opening 36 through which air is discharged from the protective case 17b is formed in the other side wall 17b. Are formed. The thermally foamed resin sheet 30 is provided on the peripheral portions of the inlet openings 34 and the outlet openings 36 in each of the side walls 17a and 17b. [Selection diagram] Fig. 3

Description

  The present invention relates to a battery module including a plurality of cylindrical batteries.

  2. Description of the Related Art Conventionally, a battery module including a plurality of cylindrical (for example, cylindrical, rectangular tube, etc.) battery cells in a close proximity is known. For example, in Patent Document 1, in a battery module configured by housing a plurality of cylindrical batteries in a casing, a cooling medium flowing from a cooling medium inlet formed at one end of the casing is cooled at the other end of the casing. The structure which cools the cylindrical battery inside a casing with a cooling medium by discharging | emitting from a medium exit is disclosed.

JP 2010-1113999 A

  The conventional battery module disclosed in Patent Document 1 does not disclose a structure for preventing the surrounding cylindrical battery from spreading when, for example, one or more cylindrical batteries are ignited due to battery abnormality or the like.

  An object of this invention is to provide the structure which can prevent a fire spread in the battery module which provided the some cylindrical battery in the proximity | contact state inside the case.

  A battery module according to the present invention is a battery module comprising a plurality of cylindrical batteries and a case that accommodates the plurality of cylindrical batteries in a state of being close to each other, and the cylinder is provided on one side wall of the case. An inlet opening through which air for cooling the battery flows into the case is formed, and an outlet opening through which air is discharged from the case is formed on the other side wall, and the inlet opening and the outlet opening on each side wall are formed. A thermal foamed resin is provided on the peripheral edge of each.

  According to the battery module of the present invention, when one or more cylindrical batteries are ignited, the heat foamed resin is expanded by the heat and the inlet opening and the outlet opening are closed. As a result, the inside of the case becomes deficient and extinguishes fire. Therefore, it is possible to prevent or suppress the spread of fire to neighboring cylindrical batteries.

It is a disassembled perspective view of the battery module which is one Embodiment of this invention. It is a figure which shows a mode that a thermofoaming resin sheet is attached to the inner wall of a protective case. It is sectional drawing in the XY plane of a battery module.

  Embodiments according to the present invention will be described below in detail with reference to the accompanying drawings. In this description, specific shapes, materials, numerical values, directions, and the like are examples for facilitating the understanding of the present invention, and can be appropriately changed according to the application, purpose, specification, and the like. In addition, when a plurality of embodiments and modified examples are included below, it is assumed from the beginning that these configurations are used in appropriate combinations.

  FIG. 1 is an exploded perspective view of a battery module 10 according to an embodiment of the present invention. In FIG. 1, three directions X, Y, and Z orthogonal to each other are indicated by arrows. In the following description, the longitudinal direction of the battery module 10 is referred to as “X direction”, the axial direction of the battery cell 12 is referred to as “Z direction”, and the direction orthogonal to the X direction and Z direction is referred to as “Y direction”.

  The battery module 10 includes a plurality of battery cells (tubular batteries) 12. In the present embodiment, the battery cell 12 is a cylindrical battery. The battery cell 12 is a chargeable / dischargeable secondary battery, such as a nickel hydride battery or a lithium ion battery housed in a cylindrical battery case. A positive electrode and a negative electrode that are electrodes of the battery cell 12 are provided at both axial ends of the battery cell 12.

  The battery module 10 illustrated in FIG. 1 has 60 battery cells 12, and the 60 battery cells 12 are arranged in an array of 4 columns and 15 rows. The 60 battery cells 12 are grouped every 15 cells to form four battery groups. Fifteen battery cells 12 belonging to the same battery group are connected in parallel by a positive electrode bus bar 23 and a negative electrode bus bar 25 described later. A battery group in which 15 battery cells 12 are connected in parallel is connected in series to another battery group or an external output terminal by an inter-group bus bar 26 described later. Note that the number of battery cells 12 and battery groups constituting the battery module 10 may be changed as appropriate.

  A discharge valve (not shown) that allows the gas generated in the battery cell 12 to be released is provided on the end face on the negative electrode side of the battery cell 12. The configuration of the discharge valve is not particularly limited as long as it can be opened when the internal pressure of the battery cell 12 increases. The discharge valve can be configured, for example, by locally thinning the outer case of the battery cell 12. When gas is generated inside the battery cell 12 due to overcharge, overdischarge, short circuit, or the like, and the internal pressure of the battery cell 12 increases, the discharge valve (thin wall portion) breaks, and the gas flows into the battery cell 12. To the outside.

  Each battery cell 12 is held upright with the directions of the positive electrode and the negative electrode aligned. In the present embodiment, the battery cell 12 is held in an upright posture with the end face where the negative electrode is located facing down (toward the smoke exhaust cover 20 side). Each battery cell 12 is accommodated in the accommodation hole 15 provided in the battery holder 14 at the lower end thereof, and held by the battery holder 14. The battery holder 14 has a substantially plate shape, and the accommodation holes 15 are two-dimensionally arranged on the plate plane. In this embodiment, the accommodation holes 15 are arranged in an array of 4 columns and 15 rows, and the accommodation holes 15 in the adjacent columns are arranged so as to be shifted by a half pitch.

  Each accommodation hole 15 has a round hole shape that fits into the cylindrical shape of the battery cell 12. The battery cell 12 is inserted into the round hole and fixed by, for example, an adhesive. The length of the accommodation hole 15 in the central axis direction is sufficiently long so that the held battery cell 12 does not wobble. Moreover, the accommodation hole 15 has penetrated the battery holder 14 in the plate | board thickness direction, and the lower end of the battery cell 12 is exposed below. The battery holder 14 is preferably made of a high heat transfer material such as aluminum in order to uniformly disperse the generated heat and reduce the temperature variation between the battery cells 12.

  The plurality of battery cells 12 held by the battery holder 14 are accommodated in a protective case (case) 16 in a state of being close to each other. The protective case 16 is made of a resin having an insulating property and has a substantially box shape with a completely open bottom. The lower end of the protective case 16 is fixed to the periphery of the battery holder 14 by, for example, fitting, screws, welding, or the like.

  A positive bus bar 23 is attached to the upper part of the protective case 16 via an insulating plate (not shown). A circular through-opening that exposes the positive electrode of the battery cell 12 is formed in the insulating plate corresponding to each battery cell 12. The through opening has a slightly smaller diameter than the outer shape of the battery cell 12. When the battery module 12 is assembled, the insulating plate is disposed in a state where the peripheral edge portion of the through opening is pressed against the upper portion of the battery cell 12. Thereby, it is comprised so that air cannot flow in into the inside from the upper direction of the protective case 16. FIG. Various wirings (for example, voltage detection wiring and temperature detection wiring) are arranged above the protective case 16, and these wirings are covered with an insulating cover 18 attached to the protective case 16.

  An inlet opening 34 and an outlet opening 36 (see FIG. 2) are formed on the peripheral surface of the protective case 16. The inlet opening 34 is an opening for allowing the air for cooling the battery cells 12 to flow into the battery module 10. The outlet opening 36 is an opening for releasing the air that has flowed into the battery module 10 to the outside. In the present embodiment, the inlet opening 34 is formed on the one side wall 17a in the X direction of the protective case 16, and the outlet opening 36 is formed on the other side surface 17b. Each of the inlet opening 34 and the outlet opening 36 includes a plurality of slit holes. The slit holes are long in the height direction (Z direction), and a plurality of slit holes are provided at intervals in the longitudinal direction (X direction). A thermally foamed resin sheet is provided on the inner surfaces of the side walls 17a and 17b of the protective case 16, which will be described later.

  A smoke exhaust cover 20 is disposed below the battery holder 14. The smoke exhaust cover 20 has a substantially boat shape with its peripheral edge raised upward. The periphery of the smoke exhaust cover 20 is fixed in close contact with the periphery of the battery holder 14 to form a sealed space with the battery holder 14. This sealed space functions as an installation space for the negative electrode bus bar 25 described later, and also functions as a smoke exhaust space 28 through which gas discharged from the battery cell 12 flows. The gas released from the battery cell 12 to the smoke exhaust space 28 is connected to the battery module via the exhaust hole 62 formed at the end of the negative electrode bus bar 25 and the exhaust passage 64 formed at the end of the battery holder 14. 10 is discharged to the outside and guided to an appropriate position by a duct or the like.

  Similarly to the protective case 16, the smoke exhaust cover 20 is also fastened to the battery holder 14. The smoke exhaust cover 20 has a fastening portion 20 a extending from the periphery of the smoke exhaust cover 20 toward the battery holder 14. The smoke exhaust cover 20 is screwed and fastened to the battery holder 14 with a screw or the like through a fastening hole provided in the fastening portion 20a. However, the smoke exhaust cover 20 may be fastened to the battery holder 14 by other fastening means such as fitting or welding.

  On both sides of the battery cell 12 in the axial direction, a positive electrode bus bar 23 and a negative electrode bus bar 25 that electrically connect the positive electrodes or the negative electrodes of the battery cells 12 are provided. The configurations of the positive electrode bus bar 23 and the negative electrode bus bar 25 are substantially the same. Therefore, the configuration of the negative electrode bus bar 25 will be mainly described below.

  The negative electrode bus bar 25 is configured by integrating the same number (four in this embodiment) of conductive plates 24 as the battery group with a resin material 43. The four conductive plates 24 are integrated with the resin material 43 in a state where the insulation is maintained with a space therebetween. The periphery of the negative electrode bus bar 25 is sandwiched and held between the smoke exhaust cover 20 and the battery holder 14.

  Each conductive plate 24 electrically connects the negative electrodes of 15 battery cells 12 constituting one battery group. The conductive plate 24 is a flat plate member made of a conductive material such as copper. The conductive plate 24 is provided with through openings 40 corresponding to the arranged battery cells 12. One through opening 40 is provided for each battery cell 12, and the lower end surface of the corresponding battery cell 12 is exposed to the smoke exhaust space 28. The through opening 40 has a slightly smaller diameter than the outer diameter of the battery cell 12. Through this through opening 40, a discharge valve provided in the battery cell 12 is exposed to the smoke exhaust space 28. The gas released from the battery cell 12 passes through the through opening 40 and reaches the smoke exhaust space 28.

  As described above, the through-opening 40 is formed to be slightly smaller in diameter than the outer diameter of the battery cell 12, so that the peripheral portion of the through-opening 40 is the lower peripheral edge of the battery cell 12 in the assembled state of the battery module 10. It is arranged in the state pressed against. Thereby, it is comprised so that air may not flow in into the inside of the protective case 16 through the through opening 40.

  A connection piece (not shown) which is a part of the conductive plate 24 is located in the through opening 40. This connection piece is in the form of a leaf spring having moderate elasticity, and is inclined so as to approach the negative electrode of the battery cell 12 as it approaches the tip. And the front-end | tip of all the connection pieces 42 contacts the negative electrode of the corresponding battery cell 12, and connects the negative electrodes of the 15 battery cells 12 electrically.

  A positive electrode bus bar 23 having a conductive plate having the same shape as the conductive plate 24 is disposed above the battery cell 12. The negative electrode bus bar 25 is configured as one component by the resin material 43, but the positive electrode bus bar 23 is assembled to the protective case 16 and integrated with the protective case 16. The conductive plate of the positive electrode bus bar 23 also electrically connects the positive electrodes of the 15 battery cells 12 constituting one battery group. The negative electrode bus bar 25 and the positive electrode bus bar 23 connect 15 battery cells 12 constituting one battery group in parallel.

  The four battery groups are connected in series by the inter-group bus bar 26. Specifically, the inter-group bus bar 26 electrically connects the conductive plate of the positive electrode bus bar 23 connected to one battery group and the conductive plate 24 of the negative electrode bus bar 25 connected to another adjacent battery group. Connecting. The inter-group bus bar 26 is a substantially flat plate member made of a conductive material such as copper, and is disposed outside the protective case 16. The inter-group bus bar 26 proceeds in the Z direction so that the upper end thereof is connected to the conductive plate of the positive electrode bus bar 23 of one battery group and the lower end thereof is connected to the conductive plate 24 of the negative electrode bus bar 25 of the adjacent battery group. As a result, it becomes a substantially parallelogram shape that also advances in the X direction.

  FIG. 2 is a diagram illustrating a state in which the thermally foamed resin sheet 30 is attached to the inner wall of the protective case 16. FIG. 3 is a cross-sectional view of the battery module on the XY plane.

  The thermally foamed resin sheet (thermally foamed resin) 30 maintains a sheet shape in the temperature range during normal use of the battery module 10, and expands and expands when the inside of the protective case 16 reaches a predetermined temperature (for example, 400 ° C.) or higher. It is formed including a foamed resin material.

  The thermally foamed resin sheet 30 is provided on each of the side walls 17 a and 17 b of the protective case 16. Specifically, the thermally foamed resin sheet 30 is a rectangular sheet having substantially the same size as the side walls 17a and 17b. A through hole 31 having a size and a shape corresponding to the inlet opening 34 and the outlet opening 36 is formed in the thermally foamed resin sheet 30. That is, the through hole 31 is a slit hole that is long in the height direction (Z direction) and is provided with a plurality of intervals in the longitudinal direction (X direction). By disposing the thermally foamed resin sheet 30 on the inner surfaces of the side walls 17a and 17b, for example, by sticking or the like, the through holes 31 of the thermally foamed resin sheet 30 are provided in the peripheral portions of the inlet opening 34 and the outlet opening 36.

  The through-hole 31 of the heat-foamed resin sheet 30 only needs to be provided at or near the periphery of the inlet opening 34 and outlet opening 36 of the side walls 17a and 17b. It may be formed larger. Thus, by forming the through-hole 31 large, it is possible to easily align the thermal foamed resin sheet 30 so as not to partially block the inlet opening 34 and the outlet opening 36. Each thermally foamed resin sheet 30 may be configured by a sheet portion divided into a plurality of parts.

  Further, the two thermally foamed resin sheets 30 may be designed such that the total volume at the time of foaming is substantially the same as the volume of the cooling air space 19 formed between the battery cells 12 in the protective case 16. . In this way, the cooling air space 19 is almost filled with the expanded thermal foamed resin, which is more effective for expelling air and preventing fire spread between battery cells.

  Next, the reason why the thermally foamed resin sheet 30 is provided in the battery module 10 of the present embodiment will be described.

  When the battery module 10 is mounted on a vehicle or the like and performs a charge / discharge operation, for example, one or more battery cells 12 included in the battery module 10 may abnormally generate heat due to, for example, an internal short circuit or the like and may ignite. At that time, when the inside of the protective case 16 reaches a predetermined temperature or higher, the thermally foamed resin sheet 30 provided on the inner surfaces of the side walls 17a and 17b expands and expands in volume. Thereby, the inlet opening 34 and the outlet opening 36 of the protective case 16 are closed, and the inflow of air into the protective case 16 is blocked. As a result, when the protective case 16 is in an oxygen deficient state, combustion in the one or more battery cells 12 is extinguished. Therefore, it is possible to prevent or suppress the spread of fire to other battery cells 12 disposed in the vicinity of the one or more battery cells 12.

  In the battery module 10, when the internal temperature is detected by a sensor or the like and the ignition of the battery cell 12 is detected, the fire extinguishing equipment provided in the battery module is operated to supply the fire extinguisher into the battery module for digestion. It is possible. However, in this case, the construction becomes complicated and the cost increases due to the installation of the fire extinguishing equipment.

  On the other hand, according to the present embodiment, it is possible to effectively prevent the fire spread between the battery cells 12 in the battery module 10 with a simple and low-cost configuration in which the thermally foamed resin sheet 30 is provided on the inner surface of the protective case 16. Or it can be suppressed.

  Moreover, since the thermally foamed resin sheet 30 also has a heat insulating function, the heat insulating material affixed on the outer surface of the battery module can be omitted.

  Further, since the through-hole 31 communicating with the inlet opening 34 and the outlet opening 36 is formed in the thermally foamed resin sheet 30, the inflow and discharge of air during normal use is not hindered, and the cooling performance of the battery cell 12 Can be maintained.

  Furthermore, the fire extinguishing in the battery module 12 by the thermally foamed resin sheet 30 does not require, for example, a power source for detecting ignition or operating digestion equipment. Accordingly, the fire extinguishing operation in the battery module 10 can be realized even when the vehicle on which the battery module 10 is mounted is left untreated (that is, the vehicle control device is not energized).

  In addition, this invention is not limited to the structure of embodiment mentioned above and its modification, A various change is possible within the matter described in the claim of this application, and its equivalent range.

  For example, in the above description, the example in which the thermally foamed resin sheet 30 is provided on the side walls 17a and 17b facing the X direction in which the inlet opening 34 and the outlet opening 36 are formed in the protective case 16 has been described, but the present invention is not limited thereto. In the case where the inlet opening and the outlet opening are formed on the two side walls facing in the Y direction in the protective case 16, a thermally foamed resin sheet may be provided on the side walls in the Y direction.

  Furthermore, although the case where the battery cell 12 is a cylindrical battery was demonstrated in the above, it is not limited to this. The battery cell may be a rectangular tube battery having a rectangular parallelepiped shape, for example.

  DESCRIPTION OF SYMBOLS 10 Battery module, 12 Battery cell, 14 Battery holder, 15 Housing hole, 16 Protective case, 18 Insulation cover, 20 Exhaust cover, 23 Positive electrode bus bar, 24 Conductive plate, 25 Negative electrode bus bar, 26 Inter-group bus bar, 28 Exhaust space , 30 Thermally foamed resin sheet (thermally foamed resin), 31 through hole, 34 inlet opening, 36 outlet opening, 40 through opening, 42 connecting piece, 43 resin material, 62 exhaust hole, 64 exhaust passage.

Claims (1)

A plurality of cylindrical batteries;
A battery module comprising a case for accommodating the plurality of cylindrical batteries in a state of being close to each other,
An inlet opening through which air for cooling the cylindrical battery flows into the case is formed on one side wall of the case, and an outlet opening through which air is discharged from the case is formed on the other side wall.
Thermal foaming resin is provided at the peripheral edge of the inlet opening and the outlet opening in each side wall,
Battery module.

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