JP2020004681A - Battery module - Google Patents

Abstract

To provide a battery module that can easily prevent the path resistance of a plurality of connection paths that electrically connect electrode terminals of a plurality of stacked battery cells and a voltage detection unit from varying for each connection path.SOLUTION: In a battery module 1 including a plurality of stacked battery cells 2, a voltage detection unit 5 that is arranged on the outer surface of the stacked battery cells 2 and electrically connected to electrode terminals 21 and 22 of the battery cells 2 so as to detect the voltage of the battery cells 2, a connection path between the electrode terminals 21 and 22 of some of the battery cells 2 and the voltage detection unit 5 is configured by a connection circuit 6 having a fixed pattern, and the electrode terminals 21 and 22 of all the battery cells 2 are electrically connected to the voltage detection unit 5 using the connection circuit 6 of the same pattern.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a battery module in which a plurality of battery cells are stacked.

  A hybrid car or an electric vehicle is equipped with a battery module configured by stacking a plurality of battery cells such as lithium ion secondary batteries. Conventionally, as such a battery module, a battery module is known in which the voltage of a battery cell is detected by a voltage detection unit to monitor the remaining capacity of the battery cell and control the charging and discharging of the battery cell ( For example, see Patent Document 1).

JP 2010-137807 A

  The voltage detection unit is configured by a plurality of electronic components, and has a housing structure in which they are housed in one housing. Generally, such a voltage detection unit is electrically connected to an electrode terminal of a battery cell by a harness. At this time, if there is an electrode terminal of a battery cell that is close to the voltage detection unit and an electrode terminal of a battery cell that is far away, the electrode terminal and the voltage are determined according to the distance between the electrode terminal and the voltage detection unit. There is a problem that the length of the connection path (harness) for electrically connecting the detection section to the detection section is different, and the path resistance varies for each connection path. If the path resistance varies, an error occurs in the detection value, and the detection accuracy may be reduced. Moreover, since it is necessary to prepare a plurality of types of harnesses having different lengths when constructing the battery module, there is a problem that the number of parts to be managed increases and the cost increases.

  Therefore, the present invention can prevent the path resistance of a plurality of connection paths that electrically connect the electrode terminals of the plurality of stacked battery cells and the voltage detection unit from varying for each connection path, and reduce the cost. It is an object to provide a possible battery module.

  (1) A battery module according to the present invention includes a plurality of stacked battery cells (for example, a battery cell 2 to be described later), and is disposed on an outer surface of the plurality of stacked battery cells, and has an electrode terminal (for example, A voltage detecting unit (for example, a voltage detecting unit 5 to be described later) that electrically detects the voltage of the battery cell by being electrically connected to a positive electrode terminal 21 and a negative terminal 22 (to be described later). In a battery module 1) described later, a connection path between the electrode terminals of some of the battery cells and the voltage detection unit is configured by a connection circuit having a fixed pattern (for example, a connection circuit 6 described later). The electrode terminals of all the battery cells are electrically connected to the voltage detection unit using the connection circuit having the same pattern.

  According to the battery module described in the above (1), all the electrode terminals of the plurality of stacked battery cells and the voltage detection unit are electrically connected by the connection circuit having the same pattern. Variations can easily be prevented from occurring every time. Further, since a plurality of connection circuits are shared by the same pattern, the number of components to be managed can be reduced, and the cost can be reduced.

  (2) In the battery module according to (1), it is preferable that the voltage detection unit has a flat shape that extends over the entire battery cell in the stacking direction.

  According to the battery module described in the above (2), the amount of protrusion of the voltage detecting portion from the outer surface of the stacked battery cells is suppressed, so that the height dimension of the battery module is suppressed and each of the battery cells is suppressed. The connection path between the electrode terminal and the voltage detection unit can be shared by the shortest path.

  (3) In the battery module according to (1) or (2), the battery cells are stacked in a plural number by arranging a terminal surface having the electrode terminal (for example, a terminal surface 2a described later) on the same surface. The voltage detection unit is disposed between the pair of positive and negative electrode terminals of each of the battery cells on the terminal surface, and the connection circuit is provided on a side surface of the voltage detection unit facing the electrode terminal (for example, a side surface described later) It is preferably provided over the side face 5a) and the electrode terminal.

  According to the battery module described in (3), since the connection circuit is disposed from the side surface of the voltage detection unit toward each electrode terminal, the connection circuit does not protrude above the voltage detection unit. The height dimension of the battery module does not increase due to connecting the connection circuit to the voltage detection unit.

  (4) In the battery module according to any one of (1) to (3), the connection circuit may include a bus bar portion (for example, a bus bar portion described later) that electrically connects the electrode terminals of the adjacent battery cells. 61), and a connecting portion (for example, a connecting portion 62 described later) for electrically connecting the bus bar portion and the voltage detecting portion, and at least the connection between the bus bar portion and the connecting portion is provided. The section is preferably configured using a flexible printed board (for example, a flexible printed board 621 described later).

  According to the battery module described in the above (4), the connection portion of each connection circuit can be made as thin as possible and can be easily bent and deformed. Therefore, this connection portion affects the height dimension of the battery module. I will not give. Further, since the flexible printed circuit board is lightweight, the battery module can also be reduced in weight.

  (5) In the battery module described in (4), it is preferable that the connection unit is detachably electrically connected to the voltage detection unit via a connector (for example, a connector 622 described later).

  According to the battery module described in the above (5), each connection circuit and the voltage detection unit can be easily connected without using soldering or the like, and the workability of assembling the battery module is excellent. Further, the connection between each connection circuit and the voltage detection unit can be easily released as needed.

  Advantageous Effects of Invention According to the present invention, it is possible to prevent the path resistance of a plurality of connection paths that electrically connect the electrode terminals of a plurality of stacked battery cells and the voltage detection unit from varying for each connection path, and to reduce the cost. A possible battery module can be provided.

1 is an overall perspective view of a battery module according to the present invention. 1 is an exploded perspective view of a battery module according to the present invention. It is a top view of the battery module concerning the present invention. FIG. 4 is a perspective view showing one connection circuit of the battery module according to the present invention. FIG. 3 is a side view of the battery module according to the present invention.

Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an overall perspective view of a battery module according to the present invention. FIG. 2 is an exploded perspective view of the battery module according to the present invention. FIG. 3 is a plan view of the battery module according to the present invention.
The battery module 1 is configured by integrally fastening a plurality of stacked battery cells 2 together with a pair of end plates 3 by a fastening member 4. Note that, in the direction shown in the drawing, the direction D1 is a direction along the stacking direction of the plurality of battery cells 2 and indicates the length direction of the battery module 1. The direction D2 is a direction orthogonal to the stacking direction of the plurality of battery cells 2 and indicates the width direction of the battery module 1. The direction D3 is a direction orthogonal to the direction in which the plurality of battery cells 2 are stacked, and indicates the height direction (vertical direction) of the battery module 1. In the direction D3, the upper side of the paper is defined as “upper”, and the lower side is defined as “lower”.

  The battery cell 2 is made of, for example, a lithium ion secondary battery, and houses an electrode body (not shown) inside a rectangular parallelepiped cell case 20 made of aluminum, an aluminum alloy, or the like. The upper surface of the battery cell 2 is covered, and serves as a terminal surface 2a on which a pair of electrode terminals of a positive electrode terminal 21 and a negative electrode terminal 22 are protruded and arranged.

  The battery cell 2 has a box shape in which the thickness along the D1 direction is sufficiently small with respect to the width along the D2 direction. As shown in FIG. 2, the plurality of battery cells 2 are arranged with their respective terminal surfaces 2a facing upward such that the terminal surfaces 2a become the same surface, and are stacked in the thickness direction. Adjacent battery cells 2 are arranged such that positive terminals 21 and negative terminals 22 are alternately arranged in a straight line when viewed in the stacking direction. Adjacent battery cells 2, 2 are insulated by holding an insulating plate 23 called a separator therebetween, and are maintained at a constant interval.

  The end plates 3 are formed of metal, resin, or a composite thereof, and are disposed at both ends in the stacking direction of a plurality of stacked battery cells 2. The end plate 3 is formed of a rectangular plate-like member similar to the side surface 2b facing the stacking direction of the battery cells 2. All the battery cells 2 are arranged so as to be sandwiched between the pair of end plates 3, and are integrally fastened by the pair of fastening members 4, 4. In addition, as shown in FIG. 2, the insulating plate 23 is also interposed between the battery cells 2 and the end plates 3 arranged at both ends in the stacking direction.

  The fastening member 4 is a metal connecting band that restrains the entire stacked battery cells 2 and the pair of end plates 3, 3, and is formed to be long along the stacking direction of the battery cells 2. The pair of fastening members 4 and 4 are arranged so as to sandwich the entire stacked battery cells 2 and the pair of end plates 3 and 3 from both sides. At both ends in the length direction (D1 direction) of the fastening members 4, 4, fixing pieces 41, 41 bent at right angles inward (to the side of the battery cell 2) are provided. The fastening member 4 is fixed to the outer surface 3a of the end plate 3 by the fixing pieces 41, 41 using an appropriate number of fixing members 42 such as bolts. As a result, a binding force is applied to all the battery cells 2 in the stacking direction between the end plates 3 by the pair of fastening members 4, 4, and expansion of the battery cells 2 due to charge and discharge is suppressed.

  In the battery module 1, a voltage detection unit 5 is arranged on the outer surface of the battery cells 2 that are stacked. The voltage detection unit 5 houses a voltage detection circuit including a plurality of electronic components (not shown) in a rectangular parallelepiped casing 50. The voltage detection unit 5 detects the voltage of each battery cell 2 via the plurality of connection circuits 6, and outputs the detection result to the outside of the battery module 1 via a signal line (not shown).

  The voltage detector 5 according to the present embodiment is disposed on the upper surface 1a of the battery module 1 including the terminal surface 2a of each battery cell 2. Specifically, the voltage detection unit 5 is disposed on the upper surface 1a of the battery module 1 between the positive terminal 21 and the negative terminal 22 on each terminal surface 2a. For this reason, the voltage detection unit 5 is placed in a plane direction (a direction parallel to the upper surface 1a of the battery module 1) with respect to the positive terminal 21 and the negative terminal 22 without being influenced by the protruding height of the positive terminal 21 and the negative terminal 22. Can be arranged in close proximity. Since the voltage detection unit 5 is disposed in contact with or close to the terminal surface 2a of each battery cell 2, for example, as compared with a case where the voltage detection unit 5 is mounted above the positive terminal 21 and the negative terminal 22, The height dimension of the battery module 1 can be reduced.

  The voltage detection unit 5 according to the present embodiment extends over the entire battery cell 2 in the stacking direction, as shown in FIGS. The voltage detection unit 5 disperses and arranges the electronic components inside the housing 50 in the planar direction, so that the electronic components are arranged in the planar direction rather than the height direction (D3 direction), specifically, in the stacking direction of the battery cells 2. Is formed so as to be long. For this reason, the voltage detection unit 5 has a flat shape in which the height (thickness) along the direction D3 is sufficiently smaller than the width along the direction D2. As a result, even if the voltage detection unit 5 is arranged on the upper surface 1a of the battery module 1, the amount of protrusion of the voltage detection unit 5 from the upper surface 1a can be suppressed, and as shown in FIG. H can also be suppressed. The voltage detecting unit 5 is fixed to the upper end surfaces 3b, 3b of the end plates 3, 3 by using fixing members 52 such as screws using mounting portions 51, 51 provided integrally at both ends in the length direction. .

  As shown in FIG. 3, the width of the voltage detection unit 5 is sufficiently smaller than the distance between a pair of electrode terminals (the positive electrode terminal 21 and the negative electrode terminal 22) protruding from the terminal surface 2 a of the battery cell 2. Thereby, a fixed distance L is provided between the voltage detection unit 5 and the positive terminal 21 and the negative terminal 22 of each battery cell 2. In the voltage detection unit 5, the two side surfaces 5 a and 5 a facing the direction D <b> 2 are arranged so as to face a row of the positive terminal 21 and the negative terminal 22 arranged along the stacking direction of the battery cells 2. Since the voltage detection unit 5 extends over the entire battery cell 2 in the stacking direction, the distance L between each positive electrode terminal 21 and each negative electrode terminal 22 and the side surface 5a, 5a of the voltage detection unit 5 is all Of the positive electrode terminal 21 and the negative electrode terminal 22.

  The voltage detection unit 5 is electrically connected to the positive terminal 21 and the negative terminal 22 of each battery cell 2 by using a plurality of connection circuits 6 having the same pattern using the two side surfaces 5a, 5a. The connection circuit 6 configures a connection path between the positive terminal 21 and the negative terminal 22 of each battery cell 2 and the voltage detection unit 5, respectively. Since the distance L between each positive electrode terminal 21 and each negative electrode terminal 22 and the side surface 5a, 5a of the voltage detecting unit 5 is equal for all the positive electrode terminals 21 and the negative electrode terminals 22, the connection path should be shared by the shortest path. Can be.

  An example of the configuration of the connection circuit 6 will be described in more detail with reference to FIG. The connection circuit 6 includes a bus bar section 61 and a connection section 62. The bus bar portion 61 electrically connects two electrode terminals of the positive electrode terminal 21 and the negative electrode terminal 22 which are adjacent in the laminating direction. The connection part 62 electrically connects the bus bar part 61 and the voltage detection part 5. The connection circuit 6 is formed into a pattern circuit by the bus bar portion 61 and the connection portion 62, and a plurality of connection circuits 6 having the same pattern (the same structure and the same shape) are connected to the positive terminals of the other adjacent battery cells 2 and 2. 21 and the negative terminal 22 and the voltage detection unit 5. Therefore, since all the connection circuits 6 in the battery module 1 are shared by one pattern, the path resistance does not vary for each connection circuit 6. In addition, since the plurality of connection circuits 6 are shared, the number of components to be managed can be reduced, and the cost of the battery module 1 can be reduced.

  The bus bar part 61 shown in this embodiment is formed of a rectangular flat metal thin plate. The bus bar portion 61 has two through holes 611 through which the electrode terminals pass. The bus bar portion 61 is fixed by inserting the positive electrode terminal 21 and the negative electrode terminal 22 into the through holes 611 and 611 and fitting them, and screwing a nut (not shown) to the positive electrode terminal 21 and the negative electrode terminal 22. Thereby, the bus bar portion 61 is fixed across the positive terminal 21 and the negative terminal 22 and electrically connects the positive terminal 21 and the negative terminal 22.

  In the bus bar portion 61 of the connection circuit 6 shown in the present embodiment, the positive terminal 21 and the negative terminal 22 to be fitted into the two through holes 611 are shifted by one on each side of the voltage detecting section 5. Accordingly, the bus bar portion 61 of each connection circuit 6 is connected to one of the pair of electrode terminals of the two battery cells 2 and 2 disposed at both ends (in the present embodiment, the positive electrode terminal 21A of the one end battery cell 2 and the other end). Except for the negative terminal 22A) of the end battery cell 2, all the adjacent positive terminals 21 and negative terminals 22 are electrically connected to connect all the battery cells 2 in series. However, in the battery module 1, all the battery cells 2 are connected in parallel by the bus bar portion 61 by arranging and stacking the positive terminal 21 and the negative terminal 22 of the adjacent battery cells 2 and 2 on the same side. You may do so.

  The connection unit 62 according to the present embodiment includes a flexible printed board 621 (hereinafter, referred to as FPC 621) and a connector 622. The FPC 621 is configured by laminating insulating layers 621B on both surfaces of a metal thin film layer 621A formed in a belt shape. On one surface of one end 621a of the FPC 621, the metal thin film layer 621A is exposed by removing a part of the insulating layer 621B. The FPC 621 abuts the exposed metal thin film layer 621A at the one end 621a on the surface of the bus bar 61, and connects the metal thin film layer 621A to the bus bar 61 with a fixing member (neither shown) such as a conductive adhesive, solder, or screw. Joined.

  The connector 622 is provided on the other end 621b of the FPC 621. The connector 622 is fitted and mounted on the connector mounting portion 53 provided on the side surface 5a of the voltage detecting portion 5 at intervals in the stacking direction, so that the FPC 621 (metal thin film layer 621A) can be detachably attached to the voltage detecting portion 5. Make an electrical connection. The battery module 1 shown in the present embodiment has six connector mounting portions 53 on one side surface 5a of the voltage detecting portion 5 and five connector mounting portions 53 on the other side surface 5a. Therefore, as shown in FIG. 3, the battery module 1 is provided such that eleven connection circuits 6 corresponding to the connector mounting portions 53 project sideways (in the direction D2).

  Since all the connection circuits 6 are connected using the side surface 5a of the voltage detection unit 5, they do not protrude above the voltage detection unit 5. For this reason, as shown in FIG. 5, the height dimension H of the battery module does not increase due to the connection of the connection circuit 6 to the voltage detection unit 5. Since the connection circuit 6 is connected to the voltage detection unit 5 by the connector 622, each connection circuit 6 and the voltage detection unit 5 can be easily connected without using solder, screws, or the like. Excellent assembly workability. Further, at the time of maintenance of the battery module 1 or replacement of parts, the connection between each connection circuit 6 and the voltage detection unit 5 can be easily released.

  Further, since the connection portion 62 of each connection circuit 6 is configured to include the FPC 621, the connection portion 62 can be made as thin as possible as compared with a case where a general wiring having a circular cross section is used. Can be easily bent and deformed. For this reason, there is no possibility that the connecting portion 62 affects the height dimension H of the battery module 1. Moreover, since the FPC 621 is lightweight, the battery module 1 can be reduced in weight.

  Note that the bus bar portion 61 of the connection circuit 6 is not limited to a metal plate, and may be made of, for example, a metal wire. In the connection circuit 6, the portion of the bus bar portion 61 may be formed by FPC integrated with the connection portion 62. Since the entire connection circuit 6 except for the connector 622 can be made into an FPC, the connection circuit 6 can be simplified, the component cost can be reduced, and the battery module 1 can be further reduced in weight. Further, the connection portion 62 of the connection circuit 6 is not limited to the connection portion detachably connected by the connector 622, and may be irremovably connected to the voltage detection portion 5.

DESCRIPTION OF SYMBOLS 1 Battery module 2 Battery cell 2a Terminal surface 21 Positive terminal (electrode terminal)
22 Negative electrode terminal (electrode terminal)
5 Voltage Detector 5a Side (of Voltage Detector) 6 Connection Circuit 61 Bus Bar 62 Connection 621 Flexible Printed Circuit Board 622 Connector

Claims (5)

A plurality of stacked battery cells, and a voltage detection unit arranged on an outer surface of the plurality of stacked battery cells and detecting a voltage of the battery cell by being electrically connected to an electrode terminal of the battery cell; A battery module comprising:
A connection path between the electrode terminals of some of the battery cells and the voltage detection unit is configured by a connection circuit having a fixed pattern,
The battery module, wherein the electrode terminals of all the battery cells are electrically connected to the voltage detection unit using the connection circuit having the same pattern.   2. The battery module according to claim 1, wherein the voltage detection unit has a flat shape extending over the entire battery cell in the stacking direction. 3. A plurality of the battery cells are stacked by arranging terminal surfaces having the electrode terminals on the same surface,
The voltage detection unit is disposed between the pair of electrode terminals of each of the battery cells on the terminal surface,
3. The battery module according to claim 1, wherein the connection circuit is provided over a side surface of the voltage detection unit facing the electrode terminal and the electrode terminal. 4. The connection circuit has a bus bar portion that electrically connects the electrode terminals of the adjacent battery cells, and a connection portion that electrically connects the bus bar portion and the voltage detection portion,
The battery module according to any one of claims 1 to 3, wherein at least the connection part of the bus bar part and the connection part is configured using a flexible printed circuit board. The battery module according to claim 4, wherein the connection unit is detachably electrically connected to the voltage detection unit via a connector.

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