JP2014229351A - Battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the looseness of an insertion member for fixing a bus bar.SOLUTION: A connection terminal 31 of a square battery has a circular inserted portion 35 extending from the distal end toward the proximal end of a shank 32. The inserted portion 35 has a female screw part 36 provided on the distal end side of the shank 32 and having a female screw part on the inner peripheral surface, and a press-fit part 37 provided closer to the proximal end side of the shank 32 than the female screw part 36. At the distal end of a bolt 41 (the end on the side opposite from the head 42), a press-fit part 43 is provided, and at the proximal end of the bolt 41, a male screw part 44 having a male screw on the outer peripheral surface is provided. The bolt 41 has the male screw part 44 to be screwed into the female screw part 36, and the press-fit part 43 to be press fitted in the press-fit part 37.

Description

  The present invention relates to a battery module in which a bus bar is fixed to a connection terminal by an insertion member.

  In a battery module having a plurality of battery cells, each battery cell is connected by a bus bar. For example, in the battery wiring module described in Patent Document 1, the bus bar is fixed with bolts. The battery wiring module has a plurality of single cells (battery cells), and each single cell has an electrode terminal. Bolt holes into which bolts are inserted are formed in the electrode terminals. Each unit cell is arranged so that the polarities of the electrode terminals of the unit cells adjacent to each other are reversed. The bus bar has an elongated rectangular shape and has an insertion hole through which a bolt is inserted. The bus bar is fixed to the electrode terminal by a bolt inserted through the insertion hole and the bolt hole, and connects the adjacent electrode terminals.

JP2013-62220A

  By the way, there is a possibility that the bolt may loosen with use in a use environment in which vibration is continuously applied to the battery module or with use over a long period of time. And if a volt | bolt remove | deviates from an electrode terminal, the electrical connection of a cell will be interrupted | blocked.

  The present invention has been made in view of such problems of the prior art, and an object of the present invention is to provide a battery module capable of suppressing loosening of an insertion member for fixing a bus bar.

  A battery module that solves the above problems includes a battery cell having an insertion portion at a connection terminal, a bus bar connected to the connection terminal of the battery cell, and the bus bar connected to the insertion portion by being inserted into the insertion portion. An insertion member that is fixed to the terminal, the connection terminal having a female screw portion and a press-fit portion in the insertion portion, and the insertion member is a male screw portion that is screwed into the female screw portion and the press-fit portion. The gist is to have a press-fitting part that is press-fitted into the part.

  According to this, in the insertion member, in addition to the press-fitting part being press-fitted into the press-fitted part, the male screw part is screwed into the female screw part. Since the press-fitting part is press-fitted into the press-fitted part, the insertion member is less likely to rotate even when trying to rotate in the direction in which the insertion member is loosened, and the insertion member is less than the case where the insertion member is formed only from the male screw part. Hard to loosen. For this reason, it is hard to remove an insertion member from a connection terminal, and it is easy to maintain the electrical connection of a battery cell.

  For the battery module, the insertion member has the press-fit portion at the distal end and the male screw portion at the proximal end of the insertion member, and the diameter of the distal end is configured to be smaller than the diameter of the proximal end, It is preferable that the insertion member is inserted into the insertion portion from the tip.

  According to this, when the male screw part of the insertion member is screwed into the female screw part of the insertion part, the press-fitting part is press-fitted into the press-fitting part. For this reason, it is easy to press-fit the press-fit portion into the press-fit portion, and the insertion member can be easily attached.

  According to the present invention, it is possible to suppress looseness of the insertion member that fixes the bus bar.

The perspective view which shows the battery module of embodiment. The perspective view which shows the square battery and battery holder of embodiment. Sectional drawing which shows the battery module of embodiment. The enlarged view of the battery module shown by A in FIG.

Hereinafter, an embodiment of the battery module will be described.
As shown in FIGS. 1 and 2, the battery module 11 includes a square battery 21 (for example, a secondary battery such as a lithium ion secondary battery or a nickel hydride storage battery) as a battery cell, and a resin battery holder 13. Are arranged side by side in a state where they are held together. In the battery module 11, end plates 14 are provided at both ends of the prismatic battery 21 in the juxtaposed direction, and the square battery 21 and the battery holder 13 are constrained by the end plate 14 to form the battery module 11. Yes. The end plate 14 is, for example, a bolt inserted from one end plate 14 toward the other end plate 14 through each end plate 14 and each battery holder 13 and nuts on the other end plate 14 side. It is fixed by being screwed together.

  The prismatic battery 21 is arranged in parallel so that the connection terminals 31 adjacent to each other in the direction in which the prismatic batteries 21 are arranged have different polarities, that is, the positive electrode terminal and the negative electrode terminal are adjacent to each other. Connection terminals 31 adjacent to each other in the direction in which the prismatic batteries 21 are arranged are connected by a bus bar B. Thereby, each square battery 21 is connected in series.

  As shown in FIG. 3, the square battery 21 has an electrode assembly 23 housed in a battery case 22. The battery case 22 includes a bottomed rectangular box-shaped main body 24 that accommodates the electrode assembly 23, and a rectangular plate-shaped lid 25 that closes an opening of the main body 24. The lid 25 is provided with connection terminals 31 (a positive terminal and a negative terminal). The electrode assembly 23 is formed by laminating a plurality of positive and negative electrodes. The connection terminal 31 is electrically connected to the electrode assembly 23 via the conductive member 26. The lid portion 25 has two through holes 27 that penetrate in the thickness direction of the lid portion 25. An insulating ring 28 is provided on the surface of the lid 25 in the thickness direction (the outer surface of the battery case 22).

  As shown in FIG. 4, the insulating ring 28 includes a circular ring-shaped first insulating portion 28 a and a cylindrical second insulating portion 28 b extending perpendicularly from the entire circumference of the inner peripheral surface of the first insulating portion 28 a. ing. The second insulating portion 28 b is inserted into the through hole 27 to cover the inner peripheral surface of the through hole 27. The first insulating portion 28 a covers the periphery of the through hole 27 on the surface in the thickness direction of the lid portion 25.

  The connection terminal 31 has a columnar shaft portion 32 that is inserted into the through hole 27 (second insulating portion 28 b) and protrudes from the battery case 22 to the outside of the battery case 22. The shaft portion 32 has a threaded portion 33 having a male screw formed on the outer peripheral surface on the tip (end portion protruding outside the battery case 22) side. Further, on the base end side of the shaft portion 32 (the end portion opposite to the tip end of the shaft portion 32), a drop prevention portion 34 having an outer shape larger than the diameter of the through hole 27 is provided. An O-ring 39 is provided between the drop prevention part 34 and the lid part 25.

  A nut N <b> 1 is screwed into the screw portion 33 of the shaft portion 32. Thereby, the connection terminal 31 is fixed to the lid portion 25. Further, the connection terminal 31 has a circular inserted portion 35 extending in the axial direction of the shaft portion 32 from the distal end of the shaft portion 32 toward the proximal end of the shaft portion 32. The inserted portion 35 includes a female screw portion 36 that is provided on the distal end side of the shaft portion 32 and has an internal thread on the inner peripheral surface, and a press-fit portion 37 that is provided on the proximal end side of the shaft portion 32 with respect to the female screw portion 36. doing. Between the female screw portion 36 and the press-fit portion 37, a taper portion 38 that is reduced in diameter from the female screw portion 36 toward the press-fit portion 37 is provided. The diameter of the female thread portion 36 is larger than the diameter of the press-fit portion 37.

  A bolt 41 as an insertion member is inserted into the inserted portion 35. The bolt 41 passes through the bus bar B and is inserted into the insertion portion 35, so that the bus bar B is pressed against the connection terminal 31 by the head portion 42 of the bolt 41, thereby fixing the bus bar B to the connection terminal 31. Yes.

  A press-fit portion 43 is provided at the front end of the bolt 41 (the end opposite to the head portion 42), and a male screw portion 44 having a male screw on the outer peripheral surface is provided at the base end of the bolt 41. The diameter of the male screw portion 44 is larger than the diameter of the press-fit portion 43. At the tip of the bolt 41, a tapered portion 47 is provided that expands from the tip surface toward the base end of the bolt 41. The diameter of the press-fit portion 43 (the diameter of the portion other than the taper portion 45 in the press-fit portion 43) is smaller than the female screw portion 36 and slightly larger than the diameter of the press-fit portion 37.

  The thermistor 51 is built in the bolt 41. More specifically, a housing portion 45 in which the thermistor 51 is housed is provided inside the press-fit portion 43, and the thermistor 51 is housed in the housing portion 45. The thermistor 51 is accommodated in the accommodating portion 45 in a state of being in contact with the bolt 41 (the inner surface of the accommodating portion 45). The thermistor 51 is preferably provided at a position close to the inside of the battery case 22. In this embodiment, the thermistor 51 is provided at a position facing the inner peripheral surface of the through hole 27.

  A hole 46 extending in the axial direction of the bolt 41 is provided from the housing portion 45 toward the head 42 of the bolt 41. A wiring 52 (signal transmission line) provided in the thermistor 51 extends to the outside of the bolt 41 through this hole 46. The wiring 52 is connected to a control device (ECU) (not shown). In the bolt 41, the male screw portion 44 is screwed into the female screw portion 36, and the press-fit portion 43 is press-fitted into the press-fit portion 37. The thermistor 51 is provided in a specific prismatic battery 21 among the plurality of prismatic batteries 21 of the battery module 11. The number of the prismatic batteries 21 provided with the thermistor 51 can be any number, and may be singular or plural.

Next, the effect | action of the battery module 11 of this embodiment is demonstrated.
The battery module 11 of this embodiment is mounted on a vehicle, for example. When the battery module 11 is continuously vibrated as the vehicle travels, the bolt 41 tends to rotate in a loosening direction. In the present embodiment, the bolt 41 is difficult to rotate by providing the press-fit portion 43 on the bolt 41. For this reason, the bolt 41 is difficult to loosen, and the bolt 41 is difficult to come off from the connection terminal 31.

  Further, the square battery 21 generates heat as it is discharged. When the prismatic battery 21 generates heat, this heat is conducted from the connection terminal 31 to the bolt 41. The thermistor 51 measures the temperature of the prismatic battery 21 by measuring the heat conducted to the bolt 41. The temperature information measured by the thermistor 51 is transmitted to the control device via the wiring 52. The control device monitors the temperature of the prismatic battery 21 from the received temperature information. When the temperature of the prismatic battery 21 is excessively increased, the control device protects the prismatic battery 21 by cutting off the discharge of the prismatic battery 21 (battery module 11).

  In the present embodiment, the thermistor 51 is provided in the press-fit portion 43 of the bolt 41. In the bolt 41, heat from the connection terminal 31 is more easily conducted in a portion having a higher degree of adhesion with the connection terminal 31. For this reason, the heat conducted from the connection terminal 31 is most easily conducted to the press-fit portion 43. For this reason, in the bolt 41, the temperature of the press-fit portion 43 is closest to the temperature of the connection terminal 31, and the temperature measurement accuracy of the prismatic battery 21 is improved by providing the thermistor 51 in the press-fit portion 43.

Therefore, according to the above embodiment, the following effects can be obtained.
(1) The thermistor 51 is built in the bolt 41. The bolt 41 is not loosened by the male screw portion 44 being screwed into the female screw portion 36 of the insertion portion 35 and the press-fitting portion 43 being press-fitted into the press-fit portion 37. For this reason, the contact state between the bolt 41 and the connection terminal 31 is easily maintained, and the contact state between the thermistor 51 and the connection terminal 31 via the bolt 41 is easily maintained. For this reason, the temperature of the square battery 21 can be measured appropriately.

  (2) Moreover, since the bolt 41 for fixing the bus bar B to the connection terminal 31 can be used as a member for attaching the thermistor 51, a dedicated member for attaching the thermistor 51 is not necessary, and the number of parts is reduced. The thermistor 51 can be attached to the prismatic battery 21 without increasing.

  (3) Since the thermistor 51 is built in the bolt 41, the thermistor 51 can be attached to the prismatic battery 21 simultaneously with the attachment of the bolt 41. Since the bolt 41 is in contact with the connection terminal 31, heat from the rectangular battery 21 is easily conducted. For this reason, the thermistor 51 can appropriately measure the temperature of the prismatic battery 21 by measuring the temperature of the bolt 41.

  (4) The thermistor 51 is provided in the press-fit portion 43 of the bolt 41. By providing the thermistor 51 in the press-fit portion 43 in which heat from the connection terminal 31 is easily conducted in the bolt 41, the temperature of the prismatic battery 21 can be measured more appropriately.

  (5) The bolt 41 has a male screw portion 44 and a press-fit portion 43. The bolt 41 is unlikely to come out of the inserted portion 35 by the male screw portion 44 being screwed into the female screw portion 36. Further, since the press-fit portion 43 is press-fitted into the press-fit portion 37, the bolt 41 is difficult to rotate and the male screw portion 44 is difficult to loosen. For this reason, the insertion state of the bolt 41 is easily maintained. That is, the bus bar B is unlikely to be detached from the connection terminal 31, and the electrical connection of the prismatic battery 21 is easily maintained.

  (6) The bolt 41 has a press-fit portion 43 at the distal end and a male screw portion 44 at the proximal end. The diameter of the press-fit portion 43 is smaller than the male screw portion 44. For this reason, when the male screw portion 44 is screwed into the female screw portion 36, the press-fit portion 43 is press-fitted into the press-fit portion 37. Therefore, it is easy to press-fit the press-fit portion 43 into the press-fit portion 37, and the bolt 41 can be easily attached.

  (7) In the prismatic battery 21, portions that generate heat are the electrode assembly 23, the conductive member 26, and the like, and are accommodated in the battery case 22. Generally, when a thermistor is attached to a battery cell, the thermistor is attached to the battery case, and the temperature of the battery case is measured as the temperature of the battery cell. In this case, the temperature difference between the heat generating part and the battery case may be large, which causes a decrease in measurement accuracy. In the present embodiment, by providing the thermistor 51 on the bolt 41, the temperature can be measured at a position close to the inside of the battery case 22 (the portion that generates heat), and the temperature measurement accuracy is improved.

  (8) Compared with the case where the thermistor 51 is brought into contact with the battery case 22 to measure the temperature, the thermistor 51 is less likely to be separated from the prismatic battery 21 due to vibration or the like, and the temperature of the prismatic battery 21 is measured stably. be able to.

In addition, you may change embodiment as follows.
In the embodiment, the battery module 11 (bolt 41) may not have the thermistor 51.

  In the embodiment, the thermistor 51 may not be built in the bolt 41. For example, the thermistor 51 may be housed in the insertion portion 35 and the thermistor 51 may be pressed against the bottom of the insertion portion 35 with the tip of the bolt 41. In this case, the adhesion between the thermistor 51 and the connection terminal 31 is improved, and the temperature of the prismatic battery 21 can be measured appropriately. Further, since the press-fit portion 43 is provided on the bolt 41, the bolt 41 is difficult to loosen. When the bolt 41 is loosened, the force with which the bolt 41 presses the thermistor 51 against the bottom of the inserted portion 35 becomes weak, the degree of adhesion between the thermistor 51 and the connection terminal 31 decreases, and as a result, the temperature of the prismatic battery 21 is appropriately measured. There is a risk that it will not be possible. By providing the press-fit portion 43 to the bolt 41 and preventing the bolt 41 from loosening, the contact state between the thermistor 51 and the connection terminal 31 can be easily maintained, and the temperature of the prismatic battery 21 can be measured appropriately.

  In the embodiment, the thermistor 51 may be provided in the male screw portion 44. In this case, since the measurement accuracy may be reduced as compared with the case where the thermistor 51 is provided in the press-fit portion 43, it is preferable to correct the measurement value by a control device or the like.

  In embodiment, the external thread part 44 may be provided in the front-end | tip of the volt | bolt 41, and the press-fit part 43 may be provided in the base end. In this case, the inserted portion 35 has a pressed-in portion 37 on the distal end side and an internally threaded portion 36 on the proximal end side.

  In embodiment, although the temperature of the volt | bolt 41 was measured and this temperature was considered as the temperature of the square battery 21, it is not restricted to this. For example, the temperature difference between the temperature of the prismatic battery 21 and the temperature of the bolt 41 may be predicted in advance and stored in the control device, and the temperature of the prismatic battery 21 may be measured in consideration of this temperature difference.

In the embodiment, a cylindrical battery or a laminate battery may be adopted as the battery cell.
In the embodiment, the battery module 11 does not have the battery holder 13 and may be configured by arranging only the square batteries 21 in parallel.

  In the embodiment, the influence of heat between the bus bar B and the connection terminal 31 may be reduced by sandwiching a heat insulating material between the bolt 41 and the bus bar B. According to this, the temperature measurement accuracy of the prismatic battery 21 is improved.

  In the embodiment, the electrode assembly 23 of the rectangular battery 21 (battery cell) may be a wound electrode assembly in which a belt-like positive electrode and a belt-like negative electrode are wound and laminated in layers. That is, the electrode assembly may be a laminated type or a wound type.

Next, a technical idea that can be grasped from the above embodiment and other examples will be described below.
(A) A secondary battery having an insertion portion into which the insertion member for fixing the bus bar to the connection terminal is inserted in the connection terminal, wherein the insertion portion includes a male screw portion provided on the insertion member. A secondary battery comprising: a female screw portion to be screwed; and a press-fit portion into which a press-fit portion provided in the insertion member is press-fitted.

  (B) The secondary battery according to the technical concept (a), characterized in that the insertion member is provided.

  B ... bus bar, 11 ... battery module, 21 ... square battery, 31 ... connection terminal, 35 ... inserted portion, 36 ... female screw portion, 37 ... pressed-in portion, 41 ... bolt, 43 ... press-fit portion, 44 ... male screw portion 51 ... Thermistor.

Claims (2)

A battery cell having a portion to be inserted in the connection terminal;
A bus bar connected to the connection terminal of the battery cell;
An insertion member for fixing the bus bar to the connection terminal by being inserted into the inserted portion,
The connection terminal has a female screw portion and a press-fit portion in the insertion portion,
The battery module according to claim 1, wherein the insertion member has a male screw portion screwed into the female screw portion and a press-fit portion press-fitted into the press-fit portion. The insertion member has the press-fit portion at the distal end, and the male screw portion at the proximal end of the insertion member,
The diameter of the distal end is configured to be smaller than the diameter of the proximal end,
The battery module according to claim 1, wherein the insertion member is inserted into the insertion portion from the tip.