JP2014116239A - Battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery module capable of further improving insulation properties, while securing heat dissipation.SOLUTION: A battery module comprises: a battery cell unit 21 having a plurality of battery cells, and a lead member 35 for electrically connecting a plurality of battery cells; a first insulation heat conductive member 41; a second insulation heat conductive member; and an outer case housing the battery cell unit 21, the first insulation heat conductive member 41 and the second insulation heat conductive member. The first insulation heat conductive member 41 is thicker than the second insulation heat conductive member, and one surface of the first insulation heat conductive member 41 gets contact with the battery cell unit 21 while deforming along an outer shape of the battery cell unit 21. The second insulation heat conductive member is arranged between the outer case and the first insulation heat conductive member 41, and gets contact with an other surface of the first insulation heat conductive member 41 and an inner surface of the outer case.

Description

  The present invention relates to a battery module having a plurality of battery cells and an outer case.

  In recent years, electric vehicles using an electric motor as a power source have been developed, and various types of electric vehicles such as two-wheeled vehicles, electric assist bicycles, electric wheelchairs, etc. have appeared in addition to four-wheeled vehicles. . As the development of electric vehicles progresses, the development of battery modules according to the type of vehicle and the user's application is also progressing, and various proposals have been made for measures against heat and insulation.

  For example, Patent Literature 1 proposes a battery temperature control device that controls the temperature of a battery by performing heat exchange with an electrode inside the battery through a terminal of the battery.

JP-A-11-354166

  It is important for the battery module to ensure not only heat dissipation but also insulation from the outside. In the battery module of Patent Document 1, an insulating heat transfer sheet is disposed between the heat sink and the conductive plate. However, as the capacity of the battery cell increases, it is required to further increase the insulation while ensuring heat dissipation. It has been.

  An object of this invention is to provide the battery module which can further improve insulation, ensuring heat dissipation.

The battery module of the present invention capable of solving the above-described problems includes a battery cell unit having a plurality of battery cells and a lead member that electrically connects the plurality of battery cells;
A first insulating heat conducting member;
A second insulating heat conducting member;
An outer case that houses the battery cell unit, the first insulating heat conducting member, and the second insulating heat conducting member;
With
The first insulating heat conducting member is thicker than the second insulating heat conducting member, and one surface of the first insulating heat conducting member is deformed along the outer surface shape of the battery cell unit. In contact with the battery cell unit,
The second insulating heat conducting member is disposed between the outer case and the first insulating heat conducting member, and is in contact with the other surface of the first insulating heat conducting member and the inner surface of the outer case. It is characterized by that.

In the battery module of the present invention, the battery cell unit has a lead wire for electrically connecting the lead member and an external electrode,
The second insulating heat conducting member has a housing portion that houses the battery cell unit,
It is preferable that the battery cell unit is accommodated in the accommodating portion in a state where the lead wire is drawn out of the accommodating portion.

  In the battery module of the present invention, it is preferable that the second insulating heat conducting member is made of a flexible film.

  In the battery module of the present invention, it is preferable that the outer case has a metal portion at least at a part of the outer surface.

  In the battery module of the present invention, it is preferable that the metal portion is in contact with the second insulating heat conducting member.

  In the battery module of the present invention, the battery cell unit has a cell holder including a plate part in which an opening through which the lead member is exposed is formed, and the first insulating heat conducting member is thicker than the plate part. It is preferable.

  According to the battery module of the present invention, since the battery cell unit is doubly insulated by the first insulating heat conducting member and the second insulating heat conducting member, extremely high insulation can be obtained.

  The first insulating heat conducting member is in contact with the battery cell unit while being deformed along the outer shape of the battery cell unit. Therefore, the first insulating heat conducting member is brought into close contact with the battery cell unit over a wide area while deforming along the uneven shape of the outer surface of the battery cell unit on the one surface side. In addition, since the first insulating heat conducting member is thicker than the second insulating heat conducting member, the first insulating heat conducting member is easily deformed so as to be in close contact with the concavo-convex shape of the outer surface of the battery cell unit, and is brought into contact with a wider area. be able to. Therefore, the heat of the battery cell unit can be efficiently conducted to the first insulating heat conducting member. Further, since the first insulating heat conducting member is thicker than the second insulating heat conducting member, the influence of the irregular shape on the outer surface of the battery cell unit appears on the other surface of the first insulating heat conducting member. First, the first insulating heat conducting member and the second insulating heat conducting member can be in good contact with each other and be in close contact with each other, and the heat of the first insulating heat conducting member can be efficiently transferred to the second insulating heat conducting member. Can conduct well.

  Further, since the first insulating heat conducting member is thicker than the second insulating heat conducting member, the heat capacity of the first insulating heat conducting member is relatively large. Therefore, much heat generated in the battery cell unit can be absorbed by the first insulating heat conducting member. On the other hand, since the second insulating heat conducting member is thinner than the first insulating heat conducting member and is in contact with both the outer case and the first insulating heat conducting member, it is transmitted from the first insulating heat conducting member. Heat can be quickly conducted to the outer case. Accordingly, the heat of the battery cell unit is efficiently and quickly transmitted to the outer case via the first insulating heat conducting member and the second insulating heat conducting member, and is efficiently and quickly dissipated to the outside.

  As described above, the battery module of the present invention can further improve the insulating property while forming a good heat dissipation path to ensure the heat dissipation and suppress the performance degradation of the battery cell due to heat. Therefore, the battery module of the present invention is suitable for increasing the capacity of the battery cell unit.

It is a perspective view which shows the external appearance of an example of embodiment of the battery module which concerns on this invention. It is the disassembled perspective view which removed the outer case in the battery module which concerns on this invention. It is a perspective view of the cell unit which comprises the battery module which concerns on this invention. (A) is sectional drawing of the battery module which concerns on this invention, (b) is the elements on larger scale of sectional drawing of a battery module. It is a disassembled perspective view of the battery module which concerns on this invention. It is a disassembled perspective view of the battery module which concerns on a modification. It is a disassembled perspective view of the battery module which concerns on other embodiment.

  Hereinafter, an example of an embodiment of a battery module according to the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the battery module 11 has an outer case 12. The outer case 12 is made of, for example, a synthetic resin such as plastic and has a rectangular parallelepiped shape.

  The battery module 11 is attached to and detached from a vehicle such as an electric bicycle, for example, and power is supplied from the battery module 11 to the electric motor of the vehicle. The battery module 11 is charged by a single charging system that is removed from the vehicle or an in-vehicle charging system that is attached to the vehicle.

  As shown in FIGS. 2 and 3, the battery module 11 contains a battery cell unit 21, a charging connector 23, an output connector 24, and a display unit 25 inside the outer case 12. The outer case 12 has a cover 13 and a lid body 14 and is configured by assembling them together. The cover 13 has a window portion 15 and a notch portion 16.

  In the outer case 12, a charging connector 23 is fitted into the window portion 15 of the cover 13, and a part of the charging connector 23 is exposed to the outside. Further, in the outer case 12, an output connector 24 is fitted into the cutout portion 16 of the cover 13, and a part of the output connector 24 is exposed to the outside. The cover 13 is also formed with a window portion (not shown) for the display portion 25, and the display portion 25 is fitted into the window portion and a part thereof is exposed to the outside.

FIG. 4 is a cross-sectional view of the battery module according to the present embodiment.
As shown in FIG. 4A, the battery cell unit 21 accommodated in the outer case 12 of the battery module 11 includes a plurality of battery cells 32 formed in a rod shape made of, for example, lithium (Li) cells. Yes. Each battery cell 32 constituting the battery cell unit 21 has both end surfaces as electrodes, and the battery cell unit 21 is configured by aligning the end surface positions of the plurality of battery cells 32 in parallel.

  The battery cell 32 is covered with a cell holder 33 made of a synthetic resin such as plastic. The cell holder 33 is formed with holes 34 at the positions where the battery cells 32 are arranged, and the battery cells 32 are fitted and held in these holes 34 so that the parallel state is maintained. The cell holder 33 includes a pair of holder divided bodies 33a, and the battery cells 32 are held by joining the holder divided bodies 33a to each other.

FIG. 5 is an exploded perspective view of the battery module according to the present embodiment.
As shown in FIG. 5, lead members 35 are provided at the end surface positions of the battery cells 32 constituting the battery cell unit 21. These lead members 35 are formed of a conductive metal plate such as copper or a copper alloy, and end faces of a predetermined number of battery cells 32 are electrically connected to each other by the lead members 35.

  Openings 36 are formed in the front and back surfaces of the plate portion 37 constituting the cell holder 33, and the lead member 35 is exposed in these openings 36.

  Further, the battery cell unit 21 includes a circuit board 22. The circuit board 22 is formed of a printed wiring board formed in a rectangular shape, and a control circuit including a CPU is formed. In the control circuit of the circuit board 22, charging control of the battery cell 32 is performed such as switching ON / OFF of charging to the battery cell 32 according to information such as temperature and current.

  A lead wire 38 (see FIG. 4) extending from the battery cell 32 is connected to the circuit board 22. Instead of using the lead wire, a part of the lead member 35 fixed to the battery cell 32 may be extended, and the extended lead member 35 may be electrically connected to the circuit board 22.

  The charging connector 23 is a connector to which a charging plug is connected when the battery cell 32 of the battery cell unit 21 is charged. The output connector 24 is connected to a vehicle-side connector when mounted on a vehicle such as an electric bicycle. Thereby, electric power feeding from the battery cell 32 of the battery module 31 to the vehicle side is enabled. The display unit 25 displays the state of charge of the battery cell 32 and the like, and is mounted with an LED and a liquid crystal display. These charging connector 23, output connector 24, and display unit 25 are all connected to the circuit board 22 by lead wires 26.

  The battery cell unit 21 is provided with a first insulating heat conducting member 41 formed in a sheet shape on both sides where the lead member 35 is exposed. As shown in FIG. 4B, the first insulating heat conducting member 41 has a thickness W1 of, for example, about 2 mm to 3 mm, and a thickness W2 of the plate portion 37 in which the opening 36 is formed. Is also big. Further, the thickness W1 of the first insulating heat conducting member 41 is larger than the depth W3 of the concavo-convex shape composed of the lead member 35 and the plate portion 37 of the battery cell unit 21. In FIG. 4B, the thickness of the portion where the first insulating heat conducting member 41 is thicker than the plate portion 37 of the cell holder 33 is indicated by the reference symbol W4.

  The first insulating heat conducting member 41 is formed of a sheet-like insulating material that has excellent heat dissipation, flexibility, and heat resistance of about 200 ° C. As the first insulating heat conducting member 41, for example, a sheet made of silicone rubber or silicone gel is used. The flexibility of the first insulating heat conducting member 41 is larger than that of the case holder 33 and the outer case 12. That is, the case holder 33 and the outer case 12 are harder than the first insulating heat conducting member 41 and are not easily deformed.

  As shown in FIG. 4B, one surface of the first insulating heat conducting member 41 is along the outer surface shape of the battery cell unit 21 (such as a concavo-convex shape including the lead member 35 and the plate portion 37). The first insulating heat conducting member 41 and the battery cell unit 21 are in close contact with each other over a wide area. As a result, the first insulating heat conducting member 41 is securely brought into close contact with the lead member 35 exposed through the opening 36 formed in the plate portion 37 of the cell holder 33.

  The battery cell unit 21 in which the first insulating heat conducting member 41 is disposed on both surfaces is covered with a second insulating heat conducting member 43 (see FIGS. 3 and 4). The second insulating heat conducting member 43 is composed of a pair of case bodies 44 formed in the same shape. The case body 44 constituting the second insulating heat conducting member 43 is formed of a flexible film excellent in insulation, durability, and waterproofness. The housing recess 45 and the entire outer edge of the housing recess 45 are formed. And a flange 46 formed on the periphery.

  As the second insulating heat conducting member 43, a material obtained by molding a resin material such as nylon, polyamide, polyethylene, polypropylene or polycarbonate by heat processing is used. In addition, as the second insulating heat conducting member 43, a base material waterproofed with cellulose can be used. The flexibility of each case body 44 constituting the second insulating heat conducting member 43 is larger than that of the case holder 33 and the outer case 12. That is, the case holder 33 and the outer case 12 are harder than the second insulating heat conducting member 43 and are not easily deformed.

  These case bodies 44 are abutted against each other with the open side of the accommodating recess 45 facing each other, and are overlapped so that the inner surfaces of the flange portions 46 are in surface contact with each other and are heat-sealed to each other. As a result, the second insulating heat conducting member 43 is formed with a housing portion 47 including the housing recess 45 of the case body 44 (see FIG. 4), and the battery cell unit 21 is housed in the housing portion 47. . Since the inner surfaces of the flange portions 46 of the case bodies 44 are heat-sealed in a state where they are in surface contact with each other, no wrinkles or the like are formed at the joint portions of the flange portions 46. Therefore, even a battery cell unit having a large volume can be accommodated in the second insulating heat conducting member 43 in a state where high waterproofness is ensured.

  In addition, the battery cell unit 21 is configured such that the lead wire 26 connected to the charging connector 23, the output connector 24, and the display unit 25 from the circuit board 22 is pulled out of the housing unit 47, and the housing recess 45 of the case body 44. It accommodates in the accommodating part 47 formed from. The flange portions 46 may be bonded to each other with an adhesive.

  The battery cell unit 21 is accommodated in the accommodating portion 47 of the second insulating heat conducting member 43, and the cover 13 constituting the outer case 12 is covered with the second insulating heat conducting member 43. And the lid 14 are housed in the outer case 12 by being assembled with each other. Since the cover 13 and the lid body 14 constituting the outer case 12 are assembled to each other, the second insulating heat conducting member 43 is disposed between the outer case 12 and the first insulating heat conducting member 41, and 1 is in close contact with and in pressure contact with the other surface of the insulating heat conducting member 41 opposite to the battery cell unit 21 and the inner surface of the outer case 12. Further, the cover 13 and the lid 14 constituting the outer case 12 are assembled to each other so that the first insulating heat conducting member 41 is pressed from the inner surface of the outer case 12 via the second insulating heat conducting member 43. Then, the battery cell unit 21 is in a state of being pressed against the concavo-convex shape including the lead member 35 and the plate portion 37. At this time, the heat-sealed flange portions 46 are accommodated in a state of being folded in the outer case 12.

  Further, as shown in FIG. 4B, the thickness W1 of the first insulating heat conducting member 41 is formed to be larger than the thickness W5 of the second insulating heat conducting member 43 (case body 44). . The second insulating heat conducting member 43 has a thickness that does not cause damage even if it contacts the inner surface of the outer case 12. Specifically, the thickness W5 of the second insulating heat conducting member 43 is about 0.1 mm.

  According to the battery module 11 having the above structure, the lead member 35 of the battery cell 32 configuring the battery cell unit 21 is double-insulated by the first insulating heat conducting member 41 and the second insulating heat conducting member 43. Therefore, extremely high insulation can be obtained.

  Further, the first insulating heat conducting member 41 is deformed along the concavo-convex shape composed of the lead member 35 and the plate portion 37 of the battery cell unit 21 on the surface of the first insulating heat conducting member 41 on the battery cell unit 21 side. However, since they are in contact with each other, the first insulating heat conducting member 41 and the battery cell unit 21 are in close contact with each other over a wide area. Further, since the thickness W1 of the first insulating heat conducting member 41 is larger than the thickness W5 of the second insulating heat conducting member, the uneven shape formed by the lead member 35 and the plate portion 37 of the battery cell unit 21 is reduced. Therefore, the first insulating heat conducting member 41 and the battery cell unit 21 are in close contact with each other over a wider area. With this configuration, the heat generated in the battery cell unit 21 can be efficiently conducted to the first insulating heat conducting member 41.

  Further, the thickness W 1 of the first insulating heat conducting member 41 is larger than the thickness W 2 of the plate portion 37 of the cell holder 33 and larger than the depth W 3 of the concavo-convex shape composed of the lead member 35 and the plate portion 37. For this reason, the first insulating heat conducting member 41 is easily deformed so as to be in close contact with the concavo-convex shape composed of the lead member 35 and the plate portion 37 without a gap.

  In addition, if the first insulating heat conducting member 41 is thinner than the plate portion 37, the uneven shape of the outer surface of the battery cell unit 21 appears on the surface of the first insulating heat conducting member 41 on the outer case 12 side. However, in this example, the first insulating heat conducting member 41 is thicker than the plate portion 37 of the cell holder 33 by the thickness W4, and the uneven shape of the battery cell unit 21 is sufficiently absorbed by the thick portion. The surface of the first insulating heat conducting member 41 on the outer case 12 side is hardly affected by the uneven shape of the battery cell unit 21. That is, the surface of the first insulating heat conducting member 41 on the outer case 12 side is not deformed due to the uneven shape of the battery cell unit 21. Accordingly, the first insulating heat conducting member 41 and the second insulating heat conducting member 43 are in close contact with each other on a large area plane and are in pressure contact with each other, and the heat transmitted to the first insulating heat conducting member 41 is transferred to the first insulating heat conducting member 41. 2 can be efficiently transmitted to the insulating heat conducting member 43.

  Further, since the first insulating heat conducting member 41 is thicker than the second insulating heat conducting member 43, the heat capacity of the first insulating heat conducting member 41 is larger than that of the second insulating heat conducting member 43. Therefore, a large amount of heat generated in the battery cell unit 21 can be absorbed by the first insulating heat conducting member 41. On the other hand, the second insulating heat conducting member 43 is thinner than the first insulating heat conducting member 41, one surface is in pressure contact with the outer case 12, and the other surface is the first insulating heat conducting member. Since the pressure contact is made while being in surface contact with the conductive member 41, the heat transmitted to the first insulating heat conductive member 41 can be quickly conducted to the outer case 12. Therefore, the heat generated in the battery cell unit 21 is efficiently and quickly transmitted to the outer case 12 via the first insulating heat conducting member 41 and the second insulating heat conducting member 43, and efficiently and quickly to the outside. Heat is dissipated.

  Thus, in the battery module 11 according to the present embodiment, it is possible to improve the insulation while forming a good heat dissipation path to ensure heat dissipation and to suppress the performance degradation of the battery cell 32 due to heat. In particular, the battery module 11 can be suitable for increasing the capacity.

  Further, since the battery cell unit 21 is accommodated in the accommodating portion 47 in a state in which the lead wire 26 is drawn out from the accommodating portion 47, electrical connection to the outside is ensured by the lead wire 26. Further, the flange portions 46 of the case bodies 44 of the second insulating heat conducting member 43 are stacked and heat-sealed so as to be in surface contact with each other, thereby accommodating the entire battery cell unit 21 and the second insulation. In addition to enhancing the insulation effect by the heat conducting member 43, it is possible to ensure good waterproofness.

  In particular, since the second insulating heat conducting member 43 is formed of a flexible film that is thin and easily deformed, the second insulating heat conducting member 43 adheres well to the first insulating heat conducting member 41 and the outer case 12. Therefore, the heat of the battery cell unit 21 can be released to the outside through the second insulating heat conducting member 43.

  As shown in FIG. 6, the outer case 12 may have a metal portion 51 on a part of its outer surface. If the outer case 12 having such a metal part 51 is used, the metal part 51 can improve penetration resistance and heat dissipation. In particular, if the metal portion is provided across the inner surface and the outer surface of the outer case 12, the metal portion 51 comes into contact with the second insulating heat conducting member 43, thereby causing the first insulating heat from the battery cell unit 21. The heat transmitted through the conductive member 41 and the second insulating heat conductive member 43 can be transmitted to the metal part 51 and can be released well by the metal part 51, and the heat dissipation can be further enhanced. In addition, the penetration resistance is increased, which means that the outer case 12 can withstand a greater impact from the outside, and the battery cell unit 21 accommodated in the outer case 12 can be protected.

Next, a battery module according to another embodiment will be described.
As shown in FIG. 7, the battery module 11 </ b> A uses a plurality of first insulating heat conducting members 41 </ b> A formed in substantially the same shape as the opening 36 of the cell holder 33. These first insulating heat conducting members 41 </ b> A are fitted into the openings 36 of the cell holder 33, and even in this form, the first insulating heat conducting members 41 </ b> A are securely in close contact with the lead members 35 exposed at the openings 36 of the cell holder 33.

  These first insulating heat conducting members 41 </ b> A are also thicker than the plate portion 37 in which the opening 36 of the cell holder 33 is formed. As a result, the first insulating heat conducting member 41 </ b> A fitted in the opening 36 slightly protrudes outward from the cell holder 33. Therefore, the second insulating heat conducting member 43 is securely adhered to the surface of the first insulating heat conducting member 41A opposite to the battery cell unit 21.

  Also in the case of the battery module 11A according to such another embodiment, the lead member 35 of the battery cell 32 constituting the battery cell unit 21 is composed of the first insulating heat conducting member 41A and the second insulating heat conducting member 43. In this case, the insulation is doubled and extremely high insulation is obtained.

  In addition, the first insulating heat conducting member 41A is in close contact with the lead member 35 of the battery cell unit 21 and is in surface contact, and the second insulating heat conducting member 43 is in contact with the outer case 12 and the first insulating heat conducting member. Since it is in surface contact with both of the members 41A, the heat of the battery cell unit 21 is transmitted well to the outer case 12 via the first insulating heat conducting member 41A and the second insulating heat conducting member 43, Heat is efficiently radiated to the outside.

  As described above, also in the battery module 11A according to another embodiment, it is possible to improve the insulation while forming a good heat dissipation path to ensure heat dissipation and to suppress the performance degradation of the battery cell 32 due to heat. .

  In the above-described embodiment, the second insulating heat conducting member 43 having a halved structure including a pair of case bodies 44 is used. As the second insulating heat conducting member 43, a flexible film is formed in a bag shape. It may be formed as follows. In this case, the battery cell unit 21 with the first insulating heat conducting member 41 attached is accommodated in the bag-like second insulating heat conducting member 43, and the outer case 12 is assembled and covered on the outside. Become.

  Moreover, although the said embodiment illustrated and demonstrated what was provided with the battery cell unit 21 which has the some battery cell 32 formed in the rod shape, this invention shows the some battery cell formed in the sheet form. The present invention is also applicable to a battery cell unit having a laminated laminate structure.

  The present invention is not limited to those exemplified in the above embodiment, and can be appropriately changed without departing from the gist of the present invention.

11, 11A: battery module, 12: outer case, 21: battery cell unit, 26: lead wire, 32: battery cell, 35: lead member, 41, 41A: first insulating heat conducting member, 43: second Insulating heat conducting member, 47: housing part, 51: metal part

Claims (6)

A battery cell unit having a plurality of battery cells and a lead member that electrically connects the plurality of battery cells;
A first insulating heat conducting member;
A second insulating heat conducting member;
An outer case that houses the battery cell unit, the first insulating heat conducting member, and the second insulating heat conducting member;
With
The first insulating heat conducting member is thicker than the second insulating heat conducting member, and one surface of the first insulating heat conducting member is deformed along the outer surface shape of the battery cell unit. In contact with the battery cell unit,
The second insulating heat conducting member is disposed between the outer case and the first insulating heat conducting member, and is in contact with the other surface of the first insulating heat conducting member and the inner surface of the outer case. A battery module characterized by The battery cell unit has a lead wire for electrically connecting the lead member and an external electrode,
The second insulating heat conducting member has a housing portion that houses the battery cell unit,
2. The battery module according to claim 1, wherein the battery cell unit is housed in the housing portion in a state where the lead wire is pulled out of the housing portion.   The battery module according to claim 2, wherein the second insulating heat conducting member is formed of a flexible film.   The battery module according to any one of claims 1 to 3, wherein the outer case has a metal portion at least at a part of an outer surface.   The battery module according to claim 4, wherein the metal part is in contact with the second insulating heat conducting member. The battery cell unit has a cell holder including a plate part in which an opening from which the lead member is exposed is formed,
The battery module according to claim 1, wherein the first insulating heat conducting member is thicker than the plate portion.

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