Battery pack

Abstract

To provide a battery pack which does not require a wire harness and enhances placement flexibility of a control circuit.SOLUTION: A battery pack 1 includes: a cell part 10; a first substrate 20 on which a first connector 21 are mounted; and a second substrate 30 on which a second connector 31 and a control circuit 32 are mounted, in which the control circuit 32 is electrically connected to the second connector 31. The first board 20 and the second board 30 establish electrical and physical connections when the first connector 21 and the second connector 31 are in contact. The connection is released when the first connector 21 and the second connector 31 are disconnected.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a battery pack. [Background technology]

[0002] Generally, in an assembled battery, wiring is required to connect the battery management system (BMS) board on which the BMS is mounted to each terminal (tab) of the battery cells in order to monitor the cell voltages of the multiple battery cells that make up the assembled battery. Conventional assembled batteries use wire harnesses for this wiring.

[0003] Due to its structure, a battery pack requires at least the same number of wire harnesses as the number of battery cells. One end of the wire harness is connected to the battery cell terminal by direct soldering, welding, connector connection, or screw connection. Similarly, the other end of the wire harness is connected to the BMS board by direct soldering, welding, connector connection, or screw connection.

[0004] Therefore, conventional battery packs using wire harnesses not only require high manufacturing costs for the wire harness itself, but also require a great deal of effort to connect the wire harnesses. Furthermore, the use of wire harnesses can lead to problems such as poor connections and burnout due to short circuits in the battery cells.

[0005] Patent Document 1 describes a battery assembly made up of multiple battery cells each having a positive electrode tab, a negative electrode tab, and a voltage detection tab, in which the positive electrode tab, the negative electrode tab, and the voltage detection tab are overlapped and welded together. The battery assembly described in Patent Document 1 can eliminate the need for a wire harness.

[0006] However, depending on the pull-out positions of the various tabs on the battery cells, it may be impossible to overlap the positive electrode tab, negative electrode tab, and voltage detection tab, making it difficult to weld the tabs together. For example, in a battery pack in which multiple battery cells are stacked in a specific stacking direction, the configuration described in Patent Document 1 may not be applicable. Furthermore, in the battery pack described in Patent Document 1, the area in which a controller (control circuit) connected to the voltage detection tab can be mounted is narrow, which limits the placement of the controller (control circuit). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2021-197349 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a battery pack that does not require a wire harness and that allows for greater freedom in arranging a control circuit. [Means for solving the problem]

[0009] In order to solve the above problems, the battery pack according to the present invention comprises: a battery section including a plurality of battery cells, each of which includes a positive electrode terminal and a negative electrode terminal drawn out in the same direction, and in which the plurality of battery cells are stacked in a predetermined stacking direction such that the positive electrode terminals and the negative electrode terminals of the plurality of battery cells protrude in the same direction; a first substrate on which a first connector is mounted and on which a plurality of wiring patterns electrically connected to the first connector and a plurality of openings are formed; a second board on which a second connector configured to be detachable from the first connector is mounted and on which a control circuit that monitors the cell voltages of each of the plurality of battery cells is mounted, the control circuit being electrically connected to the second connector; A battery pack comprising: the positive electrode terminals and the negative electrode terminals of the plurality of battery cells are electrically connected to the plurality of wiring patterns while being inserted into the plurality of openings; The first board and the second board are characterized in that an electrical and physical connection is established when the first connector and the second connector are in a connected state, and the connection is released when the first connector and the second connector are in a disconnected state.

[0010] In this configuration, the positive and negative terminals of the multiple battery cells are electrically connected to the control circuit on the second board via the wiring pattern, first connector, and second connector of the first board, eliminating the need for a wire harness. Also, in this configuration, the control circuit that monitors the cell voltages is mounted on the second board, improving the flexibility of the control circuit's placement.

[0011] In this configuration, the first board and the second board are electrically and physically connected when the first connector and the second connector are connected, and are disconnected when the first connector and the second connector are disconnected. Therefore, the battery module and the first board and the second board are manufactured separately, and the first connector of the first board and the second connector of the second board are connected in the final process, thereby shortening the time required to manufacture the battery pack. Furthermore, for example, when replacing the second board after shipping the battery pack, by disconnecting the first connector and the second connector, it is possible to replace only the second board while leaving the battery module and the first board in place.

[0012] In the battery pack, It is preferable that the positive electrode terminals and the negative electrode terminals of the battery section are alternately arranged in the stacking direction, and the positive electrode terminals and the negative electrode terminals are folded over each other so that the plurality of battery cells are connected in series, and the positive electrode terminals and the negative electrode terminals are conductively connected to the plurality of wiring patterns of the first substrate.

[0013] In the battery pack, the first substrate has a first end and a second end in a direction perpendicular to the stacking direction; the plurality of openings include a plurality of first openings formed on the first end side of the first substrate and a plurality of second openings formed on the second end side of the first substrate, the first opening is formed to the first end, The second opening may be configured to be formed to the second end.

[0014] In the battery pack, The opening width of the first opening in the stacking direction can be configured to be different from the opening width of the second opening in the stacking direction.

[0015] In the battery pack, At least one fuse may be interposed in the plurality of wiring patterns of the first substrate. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a battery pack that does not require a wire harness and allows for improved freedom in arranging a control circuit. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a side view of a battery pack according to the present invention; [Figure 2] FIG. 2 is a front view of the battery section as seen from line AA in FIG. [Figure 3] 1A is a front view of a first substrate, and FIG. 1B is a front view showing a welded portion of the first substrate. [Figure 4] 1A is a side view of the battery pack according to the present invention when the first connector and the second connector are in a detached state, and FIG. 1B is a perspective view showing the relationship between the first connector and the second connector. [Figure 5] 10A is a diagram showing a first substrate according to a first modified example, and FIG. 10B is a diagram showing a first substrate according to a second modified example. [Figure 6] FIG. 10 is a diagram showing a first substrate according to a third modified example. [Figure 7] 10A and 10B are diagrams showing a first substrate and a second substrate according to a fourth modified example, where (A) is a diagram showing a case where the second substrate is one substrate, and (B) is a diagram showing a case where the second substrate is two substrates. DETAILED DESCRIPTION OF THE INVENTION

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a battery pack according to the present invention will be described with reference to the accompanying drawings.

[0019] 1 shows a side view of a battery pack 1 according to one embodiment of the present invention. The battery pack 1 is a laminated battery pack, and includes a battery module 10, a first board 20 arranged on the front side of the battery module 10, and a second board 30 arranged on the front side of the first board 20. The first board 20 and the second board 30 are electrically and physically connected by a first connector 21 and a second connector 31, which will be described later, while maintaining a predetermined insulation distance.

[0020] The battery module 10 includes a plurality of (eight in this embodiment) battery cells 11 (11-1 to 11-8). Each battery cell 11 includes an exterior housing that contains a positive electrode, a negative electrode, a separator, and an electrolyte, and a positive electrode terminal 12 and a negative electrode terminal 13 that are pulled out in the same direction (forward) from the exterior housing. The battery cells 11 are known secondary battery cells, such as lithium-ion secondary battery cells.

[0021] Fig. 2 shows a front view of the battery module 10 as seen from line AA in Fig. 1. As shown in Fig. 2, in each battery cell 11, a positive electrode terminal 12 and a negative electrode terminal 13 are extended forward and arranged side by side in the left-right direction. The battery module 10 is formed by stacking the battery cells 11 in a predetermined stacking direction (vertical direction), with the positive electrode terminals 12 and negative electrode terminals 13 protruding alternately in the stacking direction (vertical direction). As shown in Fig. 1, the positive electrode terminals 12 and negative electrode terminals 13 are folded over each other as a pair and welded to the front surface of the first substrate 20.

[0022] 3(A) shows a front view (front view) of the first substrate 20. The first substrate 20 has a first connector 21 mounted in the center of the front surface. A plurality of wiring patterns 22a to 22i electrically connected to the first connector 21 are formed on the front surface of the first substrate 20. Furthermore, a plurality of openings 23 penetrating in the front-rear direction are formed in the first substrate 20. In this embodiment, a total of 16 openings 23 are formed, eight on each side, corresponding to eight positive electrode terminals 12 and eight negative electrode terminals 13.

[0023] The positive electrode terminal 12 or the negative electrode terminal 13 is inserted into the opening 23. The positive electrode terminal 12 and the negative electrode terminal 13 inserted into the opening 23 are folded along the front surface of the first substrate 20 so that they are folded over each other as a pair, except for the positive electrode terminal 12 of the battery cell 11-1 and the negative electrode terminal 13 of the battery cell 11-8. In other words, the battery cells 11-1 to 11-8 are connected in series.

[0024] The positive electrode terminal 12 and the negative electrode terminal 13 are welded to the first substrate 20, thereby establishing an electrical connection (conductive connection) with the wiring patterns 22a to 22i. Fig. 3(B) shows welded portions 24a to 24i on the first substrate 20. The welded portions 24a to 24i are formed by, for example, laser welding or spot welding. Note that the positive electrode terminal 12 and the negative electrode terminal 13 are not shown in Fig. 3(B).

[0025] Welding portion 24a establishes an electrical connection between the negative electrode terminal 13 of battery cell 11-1, the positive electrode terminal 12 of battery cell 11-2, and wiring pattern 22a. Welding portion 24b establishes an electrical connection between the negative electrode terminal 13 of battery cell 11-3, the positive electrode terminal 12 of battery cell 11-4, and wiring pattern 22b. Welding portion 24c establishes an electrical connection between the negative electrode terminal 13 of battery cell 11-5, the positive electrode terminal 12 of battery cell 11-6, and wiring pattern 22c. Welding portion 24d establishes an electrical connection between the negative electrode terminal 13 of battery cell 11-7, the positive electrode terminal 12 of battery cell 11-8, and wiring pattern 22d.

[0026] Welding section 24e establishes an electrical connection between the negative terminal 13 of battery cell 11-2, the positive terminal 12 of battery cell 11-3, and wiring pattern 22e. Welding section 24f establishes an electrical connection between the negative terminal 13 of battery cell 11-4, the positive terminal 12 of battery cell 11-5, and wiring pattern 22f. Welding section 24g establishes an electrical connection between the negative terminal 13 of battery cell 11-6, the positive terminal 12 of battery cell 11-7, and wiring pattern 22g.

[0027] The welded portion 24h establishes an electrical connection between the positive terminal 12 of the battery cell 11-1 and the wiring pattern 22h. The positive terminal 12 of the battery cell 11-1 serves as a positive terminal for external connection of the battery module 10. The welded portion 24i establishes an electrical connection between the negative terminal 13 of the battery cell 11-8 and the wiring pattern 22i. The negative terminal 13 of the battery cell 11-8 serves as a negative terminal for external connection of the battery module 10.

[0028] A second connector 31 is mounted in the center of the rear surface of the second substrate 30. A control circuit 32 is mounted on the front surface of the second substrate 30 for monitoring the cell voltages of each of the battery cells 11-1 to 11-8.

[0029] The first connector 21 and the second connector 31 are configured to be detachable from each other. When the first connector 21 and the second connector 31 are in an attached state, an electrical and physical connection is established between the first substrate 20 and the second substrate 30, as shown in Fig. 1. On the other hand, when the first connector 21 and the second connector 31 are in a detached state, the electrical and physical connection between the first substrate 20 and the second substrate 30 is released, as shown in Fig. 4(A). For example, board-to-board connectors can be used as the first connector 21 and the second connector 31, as shown in Fig. 4(B).

[0030] The first connector 21 includes, for example, a plurality of first contacts (at least nine in this embodiment) and a first housing that holds the plurality of first contacts. The plurality of first contacts are connected one-to-one to the wiring patterns 22a to 22i of the first substrate 20. The second connector 31 includes, for example, a plurality of second contacts (at least nine in this embodiment) and a second housing that holds the plurality of second contacts. In the mated state, the plurality of second contacts are connected one-to-one to the plurality of first contacts. The plurality of second contacts are also connected to the control circuit 32 via a wiring pattern (not shown) formed on the second substrate 30.

[0031] The control circuit 32 is, for example, a battery management system (BMS). The battery management system is composed of digital circuits including semiconductor ICs or LSIs, microcomputers, etc., and analog circuits including resistors, etc. The control circuit 32 can be placed anywhere on the front surface of the second substrate 30. Therefore, in this embodiment, the degree of freedom in placing the control circuit 32 can be improved.

[0032] As described above, control circuit 32 has the function of monitoring the cell voltages of each of battery cells 11-1 to 11-8, but may also have other functions. For example, control circuit 32 may monitor the charge / discharge currents of battery cells 11-1 to 11-8, perform control to equalize the cell voltages of battery cells 11-1 to 11-8 (cell balance control), or calculate the state of charge (SOC) of battery cells 11-1 to 11-8.

[0033] In the battery pack 1 according to this embodiment, the positive electrode terminals 12 and negative electrode terminals 13 of the battery cells 11-1 to 11-8 are electrically connected to the control circuit 32 mounted on the second substrate 30 via the wiring patterns 22a to 22i of the first substrate 20, the first connector 21, and the second connector 31. Therefore, in this embodiment, multiple wire harnesses are not required.

[0034] When multiple wire harnesses are used, variations in the lengths of the wire harnesses cause variations in the impedance (resistance value) of the wire harnesses. In contrast, in this embodiment, by adjusting the lengths of the wiring patterns 22a-22i of the first substrate 20, it is possible to reduce variations in the impedance of the wiring patterns 22a-22i. For example, by making the wiring patterns 22a-22i equal in length, it is possible to make the impedance of the wiring patterns 22a-22i the same. This allows the control circuit 32 to accurately measure the impedance of the battery cells 11-1-11-8. Note that equal-length wiring does not necessarily mean that the impedance of the wiring patterns 22a-22i is completely the same; it is sufficient if the impedance error is 10% or less.

[0035] In the battery pack 1 according to this embodiment, the first board 20 and the second board 30 are electrically and physically connected by the first connector 21 and the second connector 31. Therefore, in this embodiment, a structure for fixing the second board 30 (for example, a structure such as a screw) is not required, and the first board 20 and the second board 30 can be reliably insulated from each other in areas other than the first connector 21 and the second connector 31.

[0036] In this embodiment, for example, the battery module 10 and first board 20 and the second board 30 can be manufactured separately, and the first connector 21 and the second connector 31 can be connected in the final process, thereby shortening the time required to manufacture the battery pack 1. Furthermore, for example, when replacing the second board 30 after shipping the battery pack 1, by disconnecting the first connector 21 and the second connector 31, it is possible to replace only the second board 30 while leaving the battery module 10 and first board 20 in place. In other words, in this embodiment, maintainability can be improved.

[0037] Although the embodiment of the battery pack according to the present invention has been described above, the present invention is not limited to the above embodiment.

[0038] [First Modification] The battery pack 1 according to the above embodiment can use a first substrate 20A shown in FIG. 5A instead of the first substrate 20. The first substrate 20A has the same configuration as the first substrate 20 of the above embodiment, except that it has openings 23a and 23b instead of the opening 23. The openings 23a correspond to the "first opening" of the present invention, and eight of them are provided on the left side of the first substrate 20A. The openings 23b correspond to the "second opening" of the present invention, and eight of them are provided on the right side of the first substrate 20A.

[0039] Opening 23a is similar to opening 23 in that it penetrates in the front-rear direction, but differs from opening 23 in that it is formed to the left end 20a (corresponding to the "first end" of the present invention) of first substrate 20A. Similarly, opening 23b is similar to opening 23 in that it penetrates in the front-rear direction, but differs from opening 23 in that it is formed to the right end 20b (corresponding to the "second end" of the present invention) of first substrate 20A. First substrate 20A having openings 23a and 23b facilitates attachment (insertion) to battery module 10.

[0040] In the above embodiment, the first substrate 20 needs to be placed over the front surface of the battery unit 10 so that the positive terminal 12 or the negative terminal 13 is inserted into each opening 23 at approximately the same time, with the first substrate 20 facing parallel to the front surface of the battery unit 10. For this reason, in the case of the first substrate 20, it becomes difficult to align the openings 23 with the positive terminal 12 and the negative terminal 13, making it difficult to attach the first substrate 20 to the battery unit 10.

[0041] On the other hand, in this modified example, it is not necessary to make the first substrate 20A parallel to the front surface of the battery module 10 during installation, and it is not necessary to simultaneously insert the positive terminal 12 and the negative terminal 13 into the openings 23a and 23b. For example, during installation, the left end 20a of the first substrate 20A is brought closer to the front surface of the battery module 10, while the right end 20b is moved away from the front surface of the battery module 10, and the positive terminal 12 and the negative terminal 13 on the left side of the battery module 10 are inserted from the left end 20a side of the opening 23a. At this time, by bringing the left end 20a of the first substrate 20A closer to the positive terminal 12 and the negative terminal 13 on the left side of the battery module 10 from the right side, it is possible to perform the installation work on the battery module 10 while checking the positions of the positive terminal 12 and the negative terminal 13.

[0042] After inserting the positive electrode terminal 12 and the negative electrode terminal 13 on the left side of the battery module 10 into the opening 23a, the positive electrode terminal 12 and the negative electrode terminal 13 on the right side of the battery module 10 are inserted into the opening 23b. After that (before welding), the first substrate 20A may be slightly moved left or right to fine-tune the attachment position of the first substrate 20A. In this way, the first substrate 20A according to the first modification facilitates attachment to the battery module 10.

[0043] [Second Modification] The battery pack 1 according to the above embodiment can use a first substrate 20B shown in FIG. 5(B) instead of the first substrate 20. The first substrate 20B has the same configuration as the first substrate 20 of the above embodiment, except that it has openings 23a' and openings 23b instead of the openings 23. The openings 23a' correspond to the "first openings" of the present invention, and eight of them are provided on the left side of the first substrate 20B. The openings 23b correspond to the "second openings" of the present invention, and eight of them are provided on the right side of the first substrate 20B.

[0044] Opening 23b has the same configuration as opening 23b of the first modified example. Opening 23a' has the same configuration as opening 23a of the first modified example, except that the opening width in the vertical direction is smaller than that of opening 23a of the first modified example. Therefore, first substrate 20B makes it easy to attach to battery module 10, as in the first modified example.

[0045] The opening width in the vertical direction of opening 23a' is smaller than the opening width in the vertical direction of opening 23b. Therefore, when attaching first substrate 20B to battery module 10, the left positive electrode terminal 12 and negative electrode terminal 13 of battery module 10 are first inserted into opening 23a', thereby improving the attachment accuracy of first substrate 20B. For example, fine adjustment of first substrate 20B in the vertical direction after attachment (before welding) is not required.

[0046] [Third Modification] The battery pack 1 according to the above embodiment can use a first substrate 20C shown in Fig. 6 instead of the first substrate 20. The first substrate 20C has the same configuration as the first substrate 20, except that a fuse 25 is mounted on the first substrate 20C.

[0047] In this modification, one fuse 25 is provided in each of wiring patterns 22a, 22d, 22e, and 22g. The fuse 25 melts when a current greater than the rated current flows (for example, when a short circuit occurs between the positive electrode terminal 12 and the negative electrode terminal 13 of battery cells 11-1 to 11-8). It is sufficient that a fuse 25 is provided in at least one of wiring patterns 22a to 22i. It is also possible to provide one fuse 25 in each of all wiring patterns 22a to 22i.

[0048] [Fourth Modification] The battery pack 1 according to the above embodiment can use a first board 20D and a second board 30D shown in Fig. 7(A) instead of the first board 20 and the second board 30. The first board 20D has the same configuration as the first board 20 except that it has a plurality of first connectors 21 (two in this modification). The second board 30D has the same configuration as the second board 30 except that it has a plurality of second connectors 31 (two in this modification).

[0049] As shown in FIG. 7(B), the second board 30D may include multiple boards (board 30d and board 30d' in this modification). Board 30d and board 30d' have the same configuration. Both board 30d and board 30d' have a second connector 31 mounted on the rear surface and a control circuit 32 mounted on the front surface. The control circuit 32 is connected to the second connector 31 via a wiring pattern (not shown).

[0050] In this way, by mounting one control circuit 32 on each of the boards (boards 30d, 30d') that make up the second board 30D, it is possible to reduce the number of battery cells 11 managed by one control circuit 32. As a result, it is possible to reduce the size of the control circuit 32, improving the degree of freedom in arranging the control circuit 32. Furthermore, since the second board 30D can be replaced on a board-by-board basis (for example, by replacing only board 30d' while leaving board 30d), maintainability can be improved.

[0051] [Other variations] The first connector and second connector of the present invention can be configured as appropriate, provided that when in the attached state, an electrical and physical connection between the first board and the second board is established, and when in the detached state, the electrical and physical connection between the first board and the second board is released.

[0052] The battery section of the present invention includes a plurality of battery cells, each of which includes a positive terminal and a negative terminal drawn out in the same direction, and the configuration can be modified as appropriate as long as the plurality of battery cells are stacked in a predetermined stacking direction so that the positive terminals and negative terminals of the plurality of battery cells protrude in the same direction.

[0053] The first substrate of the present invention can be modified in configuration as appropriate, as long as it has a first connector mounted thereon and is formed with a plurality of wiring patterns electrically connected to the first connector and a plurality of openings into which positive and negative terminals can be inserted.

[0054] The second board of the present invention can be configured as appropriate as long as it is equipped with a second connector that is configured to be detachable from the first connector, a control circuit that monitors the cell voltages of each of the multiple battery cells, and the control circuit is electrically connected to the second connector. [Explanation of symbols]

[0055] 1 battery pack 10 Battery section 11(11-1~11-8) Battery cell 12 Positive terminal 13 Negative terminal 20, 20A to 20D First board 21 First connector 22a~22i wiring pattern 23, 23a, 23a', 23b opening 25 Fuse 24a~24i Welded parts 25 Fuse 30, 30D Second board 31 Second Connector 32 Control circuit

Claims

1. a battery section including a plurality of battery cells, each of which includes a positive electrode terminal and a negative electrode terminal drawn out in the same direction, and in which the plurality of battery cells are stacked in a predetermined stacking direction such that the positive electrode terminals and the negative electrode terminals of the plurality of battery cells protrude in the same direction; a first substrate on which a first connector is mounted and on which a plurality of wiring patterns electrically connected to the first connector and a plurality of openings are formed; a second board on which a second connector configured to be detachable from the first connector is mounted and on which a control circuit that monitors the cell voltages of each of the plurality of battery cells is mounted, the control circuit being electrically connected to the second connector; A battery pack comprising: the positive electrode terminals and the negative electrode terminals of the plurality of battery cells are electrically connected to the plurality of wiring patterns while being inserted into the plurality of openings; When the first connector and the second connector are in a mated state, an electrical and physical connection is established between the first board and the second board, and when the first connector and the second connector are in a detached state, the connection is released. A battery pack characterized by:

2. In the battery section, the positive electrode terminals and the negative electrode terminals are alternately arranged in the stacking direction, and the positive electrode terminals and the negative electrode terminals are folded over each other so that the plurality of battery cells are connected in series. The positive electrode terminals and the negative electrode terminals are conductively connected to the plurality of wiring patterns of the first substrate.

2. The battery pack according to claim 1, wherein the battery pack is a battery.

3. the first substrate has a first end and a second end in a direction perpendicular to the stacking direction; the plurality of openings include a plurality of first openings formed on the first end side of the first substrate and a plurality of second openings formed on the second end side of the first substrate, the first opening is formed to the first end, The second opening is formed to the second end.

2. The battery pack according to claim 1, wherein the battery pack is a battery.

4. The opening width of the first opening in the stacking direction is different from the opening width of the second opening in the stacking direction.

4. The battery pack according to claim 3.

5. At least one fuse is interposed in the plurality of wiring patterns of the first substrate.

2. The battery pack according to claim 1, wherein the battery pack is a battery.

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