Electronic device and battery module

Abstract

An electronic device (700) comprises a fuse (720) and solder (730) for holding the fuse (720). The melting point of the solder (730) is 300°C or lower.

Description

Electronic device and battery module

[0001] The present invention relates to an electronic device and a battery module.

[0002] In recent years, various battery modules have been developed. As described in Patent Document 1, a battery module may include a battery cell and a fuse that breaks when a current equal to or greater than a predetermined value flows through the battery cell.

[0003] Special Publication No. 2022-543124

[0004] A battery module may include an electronic device having electrical components electrically connected to the battery cells. Examples of the electrical components include electronic elements such as fuses, electrical circuits, and wires. Even if an overcurrent is not flowing through a circuit including the electrical components, it may be necessary to shut off the circuit including the electrical components if the temperature around the electrical components becomes relatively high.

[0005] One example of an object of the present invention is to interrupt a circuit including an electrical component when the ambient temperature of the electrical component is relatively high. Other objects of the present invention will become apparent from the description of this specification.

[0006] An aspect of the present invention is as follows: 1. An electronic device comprising: an electrical component; and a conductor that holds the electrical component, wherein the conductor has a melting point of 300°C or less. 2. The electronic device described in 1., wherein the conductor contains solder. 3. The electronic device described in 1., wherein the electrical component has a fuse. 4. A battery module comprising: the electronic device described in any one of 1. to 3.; and a battery cell electrically connected to the electrical component via the conductor. 5. The battery module described in 4., wherein at least a portion of a path for flowing gas generated from the battery cell is located around the electrical component and the conductor.

[0007] According to the above aspect of the present invention, it is possible to shut off a circuit including an electrical component when the temperature around the electrical component is relatively high.

[0008] Fig. 2 is an exploded perspective view of the upper side of the battery module according to the embodiment. Fig. 3 is a schematic cross-sectional view taken along line AA in Fig. 1. Fig. 4 is a view showing a modified example of Fig. 2.

[0009] Hereinafter, embodiments and modifications of the present invention will be described with reference to the drawings. In all the drawings, similar components are designated by similar reference numerals, and descriptions thereof will be omitted as appropriate.

[0010] FIG. 1 is an exploded top perspective view of a battery module 10 according to an embodiment.

[0011] For the purpose of explanation, FIG. 1 shows the X, Y, and Z directions. The X direction indicates the front-to-rear direction of the battery module 10. The Y direction is one of the directions perpendicular to the X direction. The Y direction indicates the left-to-right direction of the battery module 10. The Z direction is a direction perpendicular to both the X and Y directions. The Z direction indicates the up-down direction of the battery module 10. The arrows pointing to the X direction, the Y direction, and the Z direction indicate the rearward, rightward, and upward directions of the battery module 10, respectively. Hereinafter, as necessary, the tip side of an arrow indicating the X direction will be referred to as the +X side, the opposite side of the tip of the arrow indicating the X direction will be referred to as the -X side, the tip side of an arrow indicating the Y direction will be referred to as the +Y side, the opposite side of the tip of the arrow indicating the Y direction will be referred to as the -Y side, the tip side of an arrow indicating the Z direction will be referred to as the +Z side, and the opposite side of the tip of the arrow indicating the Z direction will be referred to as the -Z side. The relationship between the X direction, Y direction, and Z direction and the front-rear direction, left-right direction, and up-down direction of the battery module 10 is not limited to the above example.

[0012] The battery module 10 includes a plurality of battery cells 100 , a plurality of compression pads 200 , a first voltage detection device 300 , a second voltage detection device 400 , a module housing 500 , a positive bus bar 610 , and a negative bus bar 620 .

[0013] The multiple battery cells 100 and the multiple compression pads 200 are stacked alternately in the Y direction. Each compression pad 200 is disposed between adjacent battery cells 100 in the Y direction. Hereinafter, unless otherwise specified, a stack of battery cells 100 refers to the multiple battery cells 100 and the multiple compression pads 200 stacked alternately in the Y direction. The X-direction dimension of each battery cell 100 is the longitudinal dimension of each battery cell 100. The Z-direction dimension of each battery cell 100 is the lateral dimension of each battery cell 100. The Y-direction dimension of each battery cell 100 is the thickness dimension of each battery cell 100. The shape of each battery cell 100 is not limited to this example.

[0014] Each battery cell 100 includes a battery element (not shown), an exterior material 110, a positive electrode terminal 122, and a negative electrode terminal 124. In one example, the battery element includes a plurality of positive electrodes and a plurality of negative electrodes (not shown) stacked alternately in the Y direction, and a separator (not shown) positioned between adjacent positive electrodes and negative electrodes in the Y direction. The exterior material 110 seals the battery element and an electrolyte (not shown). The positive electrode terminal 122 is electrically connected to the positive electrode of the battery element. The positive electrode terminal 122 is drawn out from one of both sides of the exterior material 110 in the X direction. The negative electrode terminal 124 is electrically connected to the negative electrode of the battery element. The negative electrode terminal 124 is drawn out from the other side of both sides of the exterior material 110 in the X direction. However, the structure of each battery cell 100 is not limited to this example.

[0015] Each battery cell 100 may be an all-solid-state battery. In an all-solid-state battery, a solid electrolyte layer is provided in a portion corresponding to a separator. An all-solid-state battery does not contain an electrolyte solution. Unless otherwise specified, the following description will be given assuming that each battery cell 100 is a battery cell containing an electrolyte solution.

[0016] The multiple battery cells 100 are electrically connected in a combination of series and parallel. Specifically, cell groups including at least two battery cells 100 adjacent to each other in the Y direction and connected in parallel are stacked in the Y direction and connected in series. On the −X side of the stack of battery cells 100, a positive terminal 122 drawn from a battery cell 100 of one cell group connected in parallel and a negative terminal 124 drawn from a battery cell 100 of another cell group connected in parallel are electrically connected to each other, forming a terminal group 120 including the positive terminal 122 and the negative terminal 124. The positive terminal 122 and the negative terminal 124 in the terminal group 120 are joined to each other by a joining method such as laser welding. A terminal group 120 is also located on the +X side of the stack of battery cells 100. Thus, multiple cell groups are connected in series from a cell group located at one end of the stack of battery cells 100 in the Y direction to a cell group located at the other end of the stack of battery cells 100 in the Y direction. Hereinafter, unless otherwise specified, the −X side terminal group 120 refers to the terminal group 120 located on the −X side of the stack of battery cells 100, and the +X side terminal group 120 refers to the terminal group 120 located on the +X side of the stack of battery cells 100.

[0017] The electrical connection of the plurality of battery cells 100 is not limited to the above example. For example, the cell group may include three or more battery cells 100 connected in parallel. Alternatively, a stack of battery cells 100 may be formed by connecting single battery cells 100 in series.

[0018] The first voltage detecting device 300 detects the voltages of the plurality of −X side terminal groups 120. The first voltage detecting device 300 has a first holding body 310, a plurality of first voltage detecting terminals 320, and a first connector 340.

[0019] The first holder 310 covers the -X side portion of the stack of battery cells 100. The first holder 310 is, for example, an insulator such as resin. The first holder 310 defines a plurality of first openings 311. Each of the plurality of -X side terminal groups 120 is exposed toward the -X side through each of the plurality of first openings 311.

[0020] Each of the multiple first voltage detection terminals 320 is located on the -X side of each of the multiple -X side terminal groups 120. Each first voltage detection terminal 320 is, for example, a conductor such as metal. The +X side surface of each first voltage detection terminal 320 and the -X side surface of each -X side terminal group 120 are joined to each other by a joining method such as laser welding. Therefore, each first voltage detection terminal 320 and each -X side terminal group 120 are electrically connected to each other. Therefore, the first voltage detection device 300 can detect the voltage of each -X side terminal group 120 using each first voltage detection terminal 320. The multiple first voltage detection terminals 320 are integrally held by a first holder 310. Therefore, by placing the first holder 310 at an appropriate position relative to the stack of battery cells 100, each of the multiple first voltage detection terminals 320 can be positioned appropriately relative to each of the multiple -X side terminal groups 120.

[0021] The first connector 340 is provided on the first holding body 310. The first voltage detection terminals 320 and the first connector 340 are electrically connected to each other via a plurality of voltage detection lines not shown in Fig. 1. The voltage detection lines are routed between the first voltage detection terminals 320 and the first connector 340 via the first holding body 310.

[0022] The second voltage detecting device 400 detects the voltages of the plurality of +X side terminal groups 120. The second voltage detecting device 400 has a second holding body 410 and a plurality of second voltage detecting terminals 420.

[0023] The second holder 410 covers the +X side portion of the stack of battery cells 100. The second holder 410 is, for example, an insulator such as resin. The second holder 410 defines a plurality of second openings 411. Each of the plurality of +X side terminal groups 120 is exposed toward the +X side through each of the plurality of second openings 411.

[0024] Each of the multiple second voltage detection terminals 420 is located on the +X side of each of the multiple +X side terminal groups 120. Each second voltage detection terminal 420 is, for example, a conductor such as metal. The -X side surface of each second voltage detection terminal 420 and the +X side surface of each +X side terminal group 120 are joined to each other by a joining method such as laser welding. Therefore, each second voltage detection terminal 420 and each +X side terminal group 120 are electrically connected to each other. Therefore, the second voltage detection device 400 can detect the voltage of each +X side terminal group 120 using each second voltage detection terminal 420. The multiple second voltage detection terminals 420 are integrally held by a second holder 410. Therefore, by placing the second holder 410 at an appropriate position relative to the stack of battery cells 100, each of the multiple second voltage detection terminals 420 can be positioned at an appropriate position relative to each of the multiple +X side terminal groups 120.

[0025] Similar to the first voltage detection device 300, the plurality of second voltage detection terminals 420 and a connector not shown in FIG. 1 are electrically connected to each other via a plurality of voltage detection lines not shown in FIG. 1.

[0026] The module housing 500 includes a first plate 510, a second plate 520, a third plate 530, a fourth plate 540, a fifth plate 550, and a sixth plate 560. Each plate is made of a conductor such as a metal.

[0027] The first plate 510 covers the -X side portion of the stack of battery cells 100 with the first voltage detection device 300 positioned between the stack of battery cells 100 and the first plate 510. The second plate 520 covers the +X side portion of the stack of battery cells 100 with the second voltage detection device 400 positioned between the stack of battery cells 100 and the second plate 520. The third plate 530 covers the -Y side portion of the stack of battery cells 100 with the first insulating cover 532 positioned between the stack of battery cells 100 and the third plate 530. The first insulating cover 532 can electrically insulate the battery cell 100 located at one end on the -Y side from the third plate 530. The first insulating cover 532 is made of, for example, silica aerogel. The fourth plate 540 covers the +Y side portion of the stack of battery cells 100, with the second insulating cover 542 positioned between the stack of battery cells 100 and the fourth plate 540. The second insulating cover 542 electrically insulates the battery cell 100 located at the other end of the +Y side from the fourth plate 540. The second insulating cover 542 is made of, for example, silica aerogel. The fifth plate 550 covers the -Z side portion of the stack of battery cells 100, with the thermally conductive adhesive 552 positioned between the stack of battery cells 100 and the fifth plate 550. The thermally conductive adhesive 552 allows heat generated from the stack of battery cells 100 to dissipate toward the fifth plate 550. The sixth plate 560 covers the +Z side portion of the stack of battery cells 100.

[0028] The positive electrode bus bar 610 is located at the end of the first holder 310 on the -Y side. The positive electrode bus bar 610 and the -X side positive electrode terminal 122 of the cell group including the plurality of battery cells 100 located at one end on the -Y side are joined to each other by a joining method such as laser welding. Therefore, the positive electrode bus bar 610 and the cell group located at one end on the -Y side are electrically connected to each other. The positive electrode bus bar 610 functions as an external terminal for electrically connecting the battery module 10 to an external device such as another battery module.

[0029] The negative electrode bus bar 620 is located at the end of the first holder 310 on the +Y side. The negative electrode bus bar 620 and the negative electrode terminal 124 on the −X side of the cell group including the plurality of battery cells 100 located at the other end on the +Y side are joined to each other by a joining method such as laser welding. Therefore, the negative electrode bus bar 620 and the cell group located at the other end on the +Y side are electrically connected to each other. The negative electrode bus bar 620 functions as an external terminal for electrically connecting the battery module 10 to an external device such as another battery module.

[0030] 1 , the positive electrode terminal 122 at the end of a group of multiple cells connected in series is the positive electrode terminal 122 on the −X side of the cell group located at one end on the −Y side, and the negative electrode terminal 124 at the end of a group of multiple cells connected in series is the negative electrode terminal 124 on the −X side of the cell group located at the other end on the +Y side. Thus, the positive electrode bus bar 610 is disposed on the −X side and the −Y side of the stack of battery cells 100, and the negative electrode bus bar 620 is disposed on the −X side and the +Y side of the stack of battery cells 100. However, the arrangement of the positive electrode terminal 122 and the negative electrode terminal 124 at the end of a group of multiple cells connected in series may differ depending on the number of cell groups included in the stack of battery cells 100. For example, there are cases where the positive electrode terminal 122 at the end of a group of multiple cells connected in series is the positive electrode terminal 122 on the −X side of the cell group located at one end on the −Y side, and the negative electrode terminal 124 at the end of a group of multiple cells connected in series is the negative electrode terminal 124 on the +X side of the cell group located at the other end on the +Y side. In this case, the positive electrode bus bar 610 is arranged on the −X side and the −Y side of the stack of battery cells 100, and the negative electrode bus bar 620 is arranged on the +X side and the +Y side of the stack of battery cells 100.

[0031] Fig. 2 is a schematic cross-sectional view taken along line A-A in Fig. 1. The cross-section shown in Fig. 2 is a cross-section of a portion of the second voltage detection device 400 according to the embodiment. In Fig. 2, the white circle with a black dot indicating the Y direction indicates that the arrow indicating the Y direction extends from the back of the page to the front.

[0032] In the example shown in FIG. 2 , the second holder 410 includes a first holder plate 412 and a second holder plate 414. The first holder plate 412 and the second holder plate 414 have a generally plate shape perpendicular to the X direction. The first holder plate 412 and the second holder plate 414 are aligned in the X direction with the +X side surface of the first holder plate 412 and the -X side surface of the second holder plate 414 facing each other. The first holder plate 412 defines a first holder plate hole 413. The first holder plate hole 413 penetrates the first holder plate 412 in the X direction. The second holder plate 414 defines a second holder plate hole 415. The second holder plate hole 415 penetrates the second holder plate 414 in the X direction.

[0033] 2, an electronic device 700 is positioned in the gap between the +X side surface of the first holding plate 412 and the −X side surface of the second holding plate 414. The electronic device 700 includes a substrate 710, a fuse 720, and a solder 730.

[0034] The substrate 710 has a generally plate-like shape perpendicular to the X direction. The substrate 710 is, for example, a printed circuit board (PCB). The substrate 710 defines a substrate hole 711. The substrate hole 711 penetrates the substrate 710 in the X direction. A conductive pattern 712 is located on the +X side surface of the substrate 710. The conductive pattern 712 is, for example, a metal pattern.

[0035] The fuse 720 is located on the +X side surface of the substrate 710. In the example shown in Fig. 2, conductive patterns 712 are located on both sides of the fuse 720 in the Z direction. The +Z side end of the fuse 720 and the -Z side end of the +Z side conductive pattern 712 are electrically connected to each other via the +Z side solder 730. The -Z side end of the fuse 720 and the +Z side end of the -Z side conductive pattern 712 are electrically connected to each other via the -Z side solder 730.

[0036] The second voltage detection terminal 420 and the fuse 720 shown in FIG. 1 are electrically connected to each other via the conductive pattern 712 and the solder 730. The second voltage detection terminal 420 and the conductive pattern 712 are electrically connected to each other, for example, via a voltage detection line (not shown). Therefore, even if an abnormality in the battery cell 100 causes an overcurrent to flow through a circuit including the fuse 720, the circuit including the fuse 720 can be cut off by melting the fuse 720. The electronic element electrically connected to the battery cell 100 is not limited to the fuse 720. Instead of the fuse 720, other electronic elements such as a resistor, a capacitor, a coil, a transistor, or a light-emitting diode (LED) may be electrically connected to the battery cell 100.

[0037] The +Z side solder 730 joins the +Z side end of the fuse 720 to the -Z side end of the +Z side conductive pattern 712. The -Z side solder 730 joins the -Z side end of the fuse 720 to the +Z side end of the -Z side conductive pattern 712. Thus, each solder 730 holds the substrate 710 and the fuse 720 together. Therefore, when each solder 730 is not melted, it is possible to prevent the fuse 720 from being removed from the substrate 710 and the fuse 720 from falling to the -Z side.

[0038] In Figure 2 , as indicated by the arrow extending from the first retaining plate hole 413 via the substrate hole 711 to the second retaining plate hole 415, the second voltage detection device 400 defines a path P for the flow of gas generated from the battery cell 100. Relatively high-temperature gas may be generated from the battery cell 100 due to an abnormality in the battery cell 100. This gas passes through the first retaining plate hole 413 and enters the gap between the first retaining plate 412 and the substrate 710. In the example shown in Figure 2 , the Z-direction positions of the second retaining plate hole 415 and the substrate hole 711 are located on the +Z side of the Z-direction position of the first retaining plate hole 413. In the example shown in Figure 2 , the Z-direction positions of the second retaining plate hole 415 and the substrate hole 711 are approximately aligned in the Z direction. Therefore, gas that has entered the gap between the first holding plate 412 and the substrate 710 moves from the first holding plate hole 413 toward the substrate hole 711, and passes through the substrate hole 711 and the second holding plate hole 415 in that order. Therefore, this gas is discharged into the space present on the +X side of the second holding plate 414. The shape of the path P is not limited to the example shown in FIG.

[0039] In the example shown in FIG. 2 , at least a portion of path P is located around the fuse 720 and solder 730. Specifically, the fuse 720 and solder 730 are located on the −Z side of the substrate hole 711. Therefore, when relatively high-temperature gas generated from the battery cell 100 passes through path P, the temperatures around the fuse 720 and solder 730 become equal to or close to the temperature of this gas. The melting point of the solder 730 is lower than the temperature of the gas generated from the battery cell 100 due to, for example, an abnormality in the battery cell 100. Therefore, when the gas passes through path P, the solder 730 melts, and the fuse 720 detaches from the substrate 710 and falls toward the −Z side. Therefore, in the embodiment, even if no overcurrent flows through the circuit including the fuse 720, the circuit including the fuse 720 can be interrupted when the temperature around the fuse 720 becomes relatively high. Therefore, in the embodiment, the circuit including the fuse 720 can be cut off before an overcurrent flows from the battery cell 100 due to the temperature rise of the battery cell 100 caused by the gas, thereby improving the safety of the battery module 10.

[0040] The solder 730 according to the embodiment is selected as an example of a conductor that melts when the gas generated from the battery cell 100 passes through the path P. Therefore, the conductor that holds the fuse 720 is not limited to the solder 730, as long as it melts when the gas generated from the battery cell 100 passes through the path P. In one example, the melting point of the conductor that holds the fuse 720 is 300° C. or lower. In this example, the conductor can melt when the gas generated from the battery cell 100 passes through the path P.

[0041] The solder 730 according to the embodiment is also selected as an example of a conductor that does not melt when the battery module 10 is operating normally. Even when the battery module 10 is operating normally, the temperature around the fuse 720 may be higher than room temperature. Therefore, the conductor that holds the fuse 720 is not limited to the solder 730, as long as it does not melt when the battery module 10 is operating normally. In one example, the melting point of the conductor that holds the fuse 720 is 200°C or higher. In this example, the conductor can be prevented from melting when the battery module 10 is operating normally.

[0042] In the embodiment, the electronic device 700 is provided in the second voltage detection device 400. However, the location where the electronic device 700 is provided is not limited to the second voltage detection device 400. The electronic device 700 may be provided in the first voltage detection device 300 or the module housing 500, for example.

[0043] Fig. 3 is a diagram showing a modification of Fig. 2. The modification shown in Fig. 3 is similar to the example shown in Fig. 2 except for the following points.

[0044] The electronic device 700A according to the modified example has an electric circuit 720A instead of the fuse 720 according to the embodiment. The electric circuit 720A includes a PCB and an integrated circuit (IC) mounted on the PCB. The electric circuit 720A may or may not include a fuse. Even in the modified example, a circuit including the electric circuit 720A can be shut off when the ambient temperature of the electric circuit 720A becomes relatively high.

[0045] From the embodiment and the modified example, it can be said that when the solder 730 holds an electrical component, a circuit including the electrical component can be interrupted when the temperature around the electrical component is relatively high. In the embodiment, an electronic element such as a fuse 720 is exemplified as the electrical component, while in the modified example, an electrical circuit 720A is exemplified. The electrical component is not particularly limited as long as it is a component that constitutes a circuit of an electronic device. For example, the electrical component may be a wire held by the solder 730.

[0046] Although the embodiments and modifications of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various other configurations can also be adopted.

[0047] According to the present specification, the following aspects are provided: 1. An electronic device comprising: an electronic element; and a conductor that holds the electronic element, wherein the conductor has a melting point of 300°C or less. 2. The electronic device described in 1., wherein the electronic element has a fuse. 3. The electronic device described in 1. or 2., wherein the conductor contains solder. 4. A battery module comprising: the electronic device described in any one of 1. to 3.; and a battery cell electrically connected to the electronic element via the conductor. 5. The battery module described in 4., wherein at least a portion of a path for flowing gas generated from the battery cell is located around the electronic element and the conductor.

[0048] This application claims priority based on Japanese Patent Application No. 2024-028316, filed February 28, 2024, the disclosure of which is incorporated herein by reference in its entirety.

[0049] REFERENCE SIGNS LIST 10 Battery module, 100 Battery cell, 110 Exterior material, 120 Terminal group, 122 Positive electrode terminal, 124 Negative electrode terminal, 200 Compression pad, 300 First voltage detection device, 310 First holder, 311 First opening, 320 First voltage detection terminal, 340 First connector, 400 Second voltage detection device, 410 Second holder, 411 Second opening, 412 First holder plate, 413 First holder plate hole, 414 Second holder plate, 415 Second holder plate hole, 420 Second voltage detection terminal, 500 Module housing, 510 First plate, 520 Second plate, 530 Third plate, 532 First insulating cover, 540 Fourth plate, 542 Second insulating cover, 550 Fifth plate, 552 Thermally conductive adhesive, 560 Sixth plate, 610 Positive electrode bus bar, 620 Negative bus bar, 700, 700A Electronic device, 710 Board, 711 Board hole, 712 Conductive pattern, 720 Fuse, 720A Electric circuit, 730 Solder, P Path

Claims

1. An electronic device comprising: an electrical component; and a conductor for holding said electrical component, wherein said conductor has a melting point of 300°C or less.

2. The electronic device of claim 1, wherein the conductor comprises solder.

3. The electronic device according to claim 1 or 2, wherein the electrical component comprises a fuse.

4. A battery module comprising: the electronic device according to claim 1 or 2; and a battery cell electrically connected to the electrical component via the conductor.

5. The battery module according to claim 4, wherein at least a portion of the path for flowing gas generated from the battery cells is located around the electrical components and the conductors.

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