Battery and battery pack

Abstract

A battery 1 includes: an electrode assembly 10 having a positive electrode 11a and a negative electrode 11b the potential of which is different from the positive electrode 11a; an exterior member 40 that includes a first main surface 41a having a first opening 41b and a second main surface 42a having a second opening 42b, and that houses the electrode assembly 10; and a first conductor 20 and a second conductor 30 electrically connected to the positive electrode 11a inside the exterior member 40. The exterior member 40 is electrically connected to the negative electrode 11b. The first main surface 41a and the second main surface 42a are opposite to each other across the electrode assembly 10. The first conductor 20 has a first exposed part 21 exposed from the first opening 41b. The second conductor 30 has a second exposed part 31 exposed from the second opening 42b.

Description

Batteries and battery packs

[0001] The present disclosure relates to batteries and battery packs.

[0002] Patent Document 1 discloses a film-covered battery as an example of a battery. The battery in Patent Document 1 includes a positive electrode connection terminal and a negative electrode connection terminal exposed from the exterior film. The positive electrode connection terminal and the negative electrode connection terminal face opposite each other. As a result, when multiple batteries are stacked, the multiple batteries are electrically connected in series.

[0003] Japanese Patent Application Laid-Open No. 2008-016368

[0004] In the battery of Patent Document 1, a separate member must be used to electrically connect multiple batteries in parallel. On the other hand, there is a demand for a simple method for electrically connecting multiple batteries in parallel.

[0005] The present disclosure has been made in view of the above, and has an object to provide a battery and a battery pack that can be easily electrically connected in parallel.

[0006] The battery of the present disclosure comprises: an electrode assembly having a first electrode and a second electrode having a potential different from that of the first electrode; an exterior member including a first main surface having a first opening and a second main surface having a second opening, the exterior member housing the electrode assembly; and a first conductor and a second conductor electrically connected to the first electrode inside the exterior member, the exterior member electrically connecting to the second electrode, the first main surface and the second main surface being on opposite sides of the electrode assembly, the first conductor having a first exposed portion exposed from the first opening, and the second conductor having a second exposed portion exposed from the second opening.

[0007] The battery pack of the present disclosure includes two of the above-described batteries, wherein the first main surface of a first battery of the two batteries is electrically connected to the second main surface of a second battery of the two batteries, and the first conductor of the first battery is electrically connected to the second conductor of the second battery.

[0008] According to the battery and battery pack of the present disclosure, electrical parallel connection can be easily achieved.

[0009] FIG. 1 is a plan view of a battery according to an embodiment of the present disclosure. FIG. 2 is a cross-sectional view of the battery taken along line II-II shown in FIG. 1. FIG. 3 is a plan view of a battery according to a first modified example of the embodiment of the present disclosure. FIG. 4 is a plan view of a battery according to a second modified example of the embodiment of the present disclosure. FIG. 5 is a plan view of a battery according to a third modified example of the embodiment of the present disclosure. FIG. 6 is a top view of a battery pack according to an embodiment of the present disclosure. FIG. 7 is a cross-sectional view of the battery pack taken along line VII-VII shown in FIG. 6.

[0010] Hereinafter, embodiments will be described in detail with reference to the drawings. Note that the present disclosure is not limited to these embodiments. Each embodiment is an example, and it goes without saying that partial substitution or combination of the configurations shown in different embodiments is possible.

[0011] The X direction shown in the drawings corresponds to the width direction of the battery 1, the Y direction corresponds to the depth direction of the battery 1, and the Z direction corresponds to the height direction of the battery 1. The X, Y, and Z directions are perpendicular to one another. In the X direction, the side indicated by the arrow is the +X side, and the side opposite the +X side is the -X side. In the Y direction, the side indicated by the arrow is the +Y side, and the side opposite the +Y side is the -Y side. In the Z direction, the side indicated by the arrow is the +Z side, and the side opposite the +Z side is the -Z side. Note that the X, Y, and Z directions are merely examples, and the present disclosure is not limited to these directions. In this specification, "planar view" refers to viewing an object along the Z direction.

[0012] <Battery 1> Fig. 1 is a plan view of a battery 1 according to an embodiment of the present disclosure. Fig. 2 is a cross-sectional view of the battery 1 taken along line II-II shown in Fig. 1.

[0013] The battery 1 is a secondary battery. The battery 1 is, for example, a lithium battery. The battery 1 is flat. The battery 1 includes an electrode assembly 10, a first conductor 20, a second conductor 30, and an exterior member 40. The electrode assembly 10, the first conductor 20, and the second conductor 30 are housed in the exterior member 40. The exterior member 40 also contains an electrolyte.

[0014] The electrode assembly 10 includes two electrode bodies 11 and a current collector 12. The electrode bodies 11 and the current collector 12 are each in the form of a sheet.

[0015] The electrode assembly 11 includes a positive electrode 11a (corresponding to a "first electrode"), a negative electrode 11b (corresponding to a "second electrode") that has a different potential from the positive electrode 11a, and a separator 11c. The positive electrode 11a, the negative electrode 11b, and the separator 11c are each in a sheet form. The positive electrode 11a and the negative electrode 11b are stacked with the separator 11c interposed between them. The two electrode assemblies 11 are arranged on opposite sides of the current collector 12.

[0016] The positive electrode 11a contains a lithium-containing composite oxide (e.g., lithium cobalt oxide, lithium nickel oxide, lithium iron phosphate, etc.). The positive electrode 11a may contain a ternary positive electrode material (e.g., NMC, NCA, etc.). The negative electrode 11b contains lithium titanate. The negative electrode 11b may contain silicon oxide and graphite, or a mixture of silicon oxide and graphite.

[0017] The positive electrodes 11a of the two electrode bodies 11 are in contact with and electrically connected to the current collector 12. The material of the current collector 12 is aluminum.

[0018] The first conductor 20 and the second conductor 30 each have a rectangular column shape extending along the Z direction. Needless to say, the first conductor 20 and the second conductor 30 are not limited to a rectangular column shape. The first conductor 20 and the second conductor 30 are disposed on opposite sides of the current collector 12 and are electrically connected to the current collector 12. In other words, the first conductor 20 and the second conductor 30 correspond to positive electrode terminals that are electrically connected to the positive electrode 11 a.

[0019] Furthermore, the first conductor 20 and the second conductor 30 overlap each other in a plan view of the battery 1. The first conductor 20 and the second conductor 30 are joined to the current collector 12. The first conductor 20 and the second conductor 30 are joined to the current collector 12 by, for example, laser welding. The first conductor 20 and the second conductor 30 and the current collector 12 may also be joined using conductive adhesive tape. Alternatively, a metal foil may be disposed between the first conductor 20 and the second conductor 30 and the current collector 12, and pressed by the exterior member 40 to fix the first conductor 20 and the second conductor 30 to the current collector 12.

[0020] The exterior member 40 has a rectangular shape in a plan view. Specifically, the periphery of the exterior member 40 has a rectangular shape in a plan view and has a first side S1, a second side S2, a third side S3, and a fourth side S4. It goes without saying that the exterior member 40 is not limited to a rectangular shape in a plan view, and the periphery of the exterior member 40 may have any shape as long as it has at least the third side S3 in a plan view.

[0021] The exterior member 40 is electrically conductive. The material of the exterior member 40 is, for example, copper. The exterior member 40 has a shape in which a single sheet member is folded at a folding portion B. The folding portion B corresponds to the third side S3. The exterior member 40 has a first exterior portion 41 and a second exterior portion 42 that are folded at the folding portion B and overlap each other. The first exterior portion 41 and the second exterior portion 42 are located on opposite sides of the electrode assembly 10. The first exterior portion 41 and the second exterior portion 42 are continuous at the folding portion B.

[0022] Furthermore, in a plan view of the exterior member 40, the peripheral edge of the first exterior portion 41 and the peripheral edge of the second exterior portion 42 are joined at portions corresponding to the first side S1, the second side S2, and the fourth side S4. The first exterior portion 41 and the second exterior portion 42 are joined by, for example, laser welding.

[0023] The two-dot chain line in FIG. 1 indicates the position of the joint portion J between the first exterior portion 41 and the second exterior portion 42. In a plan view of the battery 1, the joint portion J is located outside the electrode body 11, the current collector 12, the first conductor 20, the second conductor 30, and the first insulating member 50 and the second insulating member 60 described below. Furthermore, as described above, the third side S3 corresponds to the folded portion B. Therefore, in a plan view of the exterior portion 40, the entire peripheral edge of the exterior portion 40 is sealed. This prevents the electrolyte from leaking between the first exterior portion 41 and the second exterior portion 42.

[0024] The first exterior portion 41 and the second exterior portion 42 are electrically connected at the joint portion J. The first exterior portion 41 and the second exterior portion 42 are electrically connected at the bent portion B. That is, the first exterior portion 41 and the second exterior portion 42 are electrically connected around the entire periphery of the exterior member 40 in a plan view of the battery 1.

[0025] Joining by laser welding can reduce the width of the joint J compared to joining using an adhesive member, such as heat welding using a resin member. Therefore, in the case of joining by laser welding, the internal volume of the exterior member 40 and the volume of the electrode body 11 can be increased compared to joining using an adhesive member. Therefore, the battery capacity (so-called energy density) relative to the size of the exterior member 40 can be increased.

[0026] The first exterior part 41 and the second exterior part 42 are in contact with the negative electrode 11b and electrically connected to it. That is, the exterior member 40 corresponds to a negative electrode terminal.

[0027] The first exterior portion 41 includes a first main surface 41 a. The second exterior portion 42 includes a second main surface 42 a. The first main surface 41 a and the second main surface 42 a are each a part of the outer surface of the exterior member 40.

[0028] The first main surface 41 a and the second main surface 42 a are flat and are located on opposite sides of the electrode assembly 10. Specifically, the first main surface 41 a and the second main surface 42 a face opposite sides in the Z direction. A plan view of the first main surface 41 a is the same as a plan view of the battery 1.

[0029] The first main surface 41a has a first opening 41b. The second main surface 42a has a second opening 42b. The first opening 41b and the second opening 42b overlap each other in a plan view of the first main surface 41a.

[0030] In addition, in a plan view of the first main surface 41a, the first conductor 20 is located inside the first opening 41b. The first conductor 20 has a first exposed portion 21 exposed from the first opening 41b. The first exposed portion 21 has a first exposed surface 21a (corresponding to an "exposed surface") that is on the same plane as the first main surface 41a.

[0031] Furthermore, in a plan view of the second main surface 42a, the second conductor 30 is located inside the second opening 42b. The second conductor 30 has a second exposed portion 31 exposed from the second opening 42b. The first exposed portion 21 and the second exposed portion 31 overlap each other in a plan view of the first main surface 41a. The second exposed portion 31 has a second exposed surface 31a that is flush with the second main surface 42a.

[0032] The first opening 41b, the second opening 42b, the first conductor 20, and the second conductor 30 are located on the +Y side of the center in the Y direction, and in a plan view of the first main surface 41a, are located near a first corner C1 defined by the first side S1 and the fourth side S4 of the exterior member 40. It goes without saying that the positions of the first opening 41b, the second opening 42b, and the first conductor 20 and the second conductor 30 are not limited to those shown in FIGS.

[0033] The battery 1 further includes a first insulating member 50 (corresponding to the “insulating member”) and a second insulating member 60 .

[0034] The first insulating member 50 is disposed between the exterior member 40 and the first conductor 20, and electrically insulates the exterior member 40 from the first conductor 20. The first insulating member 50 has a cylindrical shape extending in the Z direction, and the first conductor 20 passes through it. The material of the first insulating member 50 is a thermoplastic resin having electrical insulation properties.

[0035] The first insulating member 50 seals the first opening 41b. Specifically, a first end face 51 on the −Z side of the first insulating member 50 is joined to the current collector 12, and a second end face 52 on the +Z side of the first insulating member 50 is joined to the periphery of the first opening 41b. The first insulating member 50, the current collector 12, and the exterior member 40 are joined together by, for example, thermal welding.

[0036] The second insulating member 60 is disposed between the exterior member 40 and the second conductor 30, and electrically insulates the exterior member 40 from the second conductor 30. The second insulating member 60 has a cylindrical shape extending in the Z direction, and the second conductor 30 passes through it. The material of the second insulating member 60 is a thermoplastic resin having electrical insulating properties.

[0037] The second insulating member 60 also seals the second opening 42b. Specifically, a first end face 61 on the +Z side of the second insulating member 60 is joined to the current collector 12, and a second end face 62 on the −Z side of the second insulating member 60 is joined to the periphery of the second opening 42b. The second insulating member 60, the current collector 12, and the exterior member 40 are joined by, for example, thermal welding. This prevents the electrolyte from leaking from the first opening 41b and the second opening 42b.

[0038] As described above, the first conductor 20 and the second conductor 30 correspond to the positive electrode terminal, and the exterior member 40 corresponds to the negative electrode terminal. Therefore, both the positive electrode terminal and the negative electrode terminal are located on the first main surface 41a side and the second main surface 42a side of the battery 1. Therefore, in a device using the battery 1, the battery 1 can be attached to the device regardless of the orientation of the battery 1 (first main surface 41a side or second main surface 42a side).

[0039] Furthermore, stacking multiple batteries 1 allows the multiple batteries 1 to be easily connected electrically in parallel. Figure 2 shows two batteries 1a, 1b stacked and electrically connected in parallel. As shown in Figure 2, when the two batteries 1a, 1b are stacked, the second conductor 30 of one battery 1a and the first conductor 20 of the other battery 1b come into contact with each other and are electrically connected, and the second main surface 42a of one battery 1a and the first main surface 41a of the other battery 1b come into contact with each other and are electrically connected.

[0040] Similarly, three or more batteries 1 can be electrically connected in parallel by stacking three or more batteries 1. In this way, the batteries 1 can be easily electrically connected in parallel without using any additional components.

[0041] Next, a battery 1 according to a modification of the above embodiment will be described, focusing mainly on the differences from the battery 1 of the above embodiment.

[0042] For example, the first conductor 20 may protrude from the first opening 41b. In this case, the first exposed portion 21 is located outside the exterior member 40 and flush with the first main surface 41a. Similarly, the second conductor 30 may protrude from the second opening 42b. In this case, when two batteries 1a, 1b are electrically connected in parallel, an electrically conductive member may be disposed between the exterior member 40 of one battery 1a and the exterior member 40 of the other battery 1b.

[0043] Furthermore, the first exposed portion 21 of the first conductor 20 may be located inside the exterior member 40 and flush with the first main surface 41a. Similarly, the second exposed portion 31 of the second conductor 30 may be located inside the exterior member 40 and flush with the second main surface 42a. In this case, when two batteries 1a, 1b are electrically connected in parallel, an electrically conductive member may be disposed between the first conductor 20 of one battery 1a and the second conductor 30 of the other battery 1b.

[0044] Furthermore, the first conductor 20 and the second conductor 30 may be positioned so as not to overlap each other in a plan view of the first main surface 41 a. In this case, the first opening 41 b and the second opening 42 b may be positioned so as not to overlap each other in a plan view of the first main surface 41 a.

[0045] Alternatively, the electrode body 11 may be configured so that the negative electrode 11b is electrically connected to the current collector 12 and the positive electrode 11a is electrically connected to the exterior member 40. In this case, the negative electrode 11b corresponds to the "first electrode" and the positive electrode 11a corresponds to the "second electrode." In this case, the exterior member 40 corresponds to the positive electrode terminal, and the first conductor 20 and the second conductor 30 correspond to the negative electrode terminal. In this case, the current collector 12 is made of copper, and the exterior member 40 is made of aluminum.

[0046] 3 is a plan view of a battery 1 according to a first modified example of the embodiment of the present disclosure. In this first modified example, the first exterior portion 41 and the second exterior portion 42 are separate bodies, and the exterior member 40 does not include a folded portion B. In this case, in a plan view of the exterior member 40, the joint portion J between the first exterior portion 41 and the second exterior portion 42, indicated by a two-dot chain line, extends along the entire periphery of the exterior member 40.

[0047] 4 is a plan view of a battery 1 according to a second modification of the embodiment of the present disclosure. In this second modification, a thermoplastic resin is disposed between the first exterior portion 41 and the second exterior portion 42 at the peripheral edge portions corresponding to the first side S1, the second side S2, and the fourth side S4 of the exterior member 40, and the first exterior portion 41 and the second exterior portion 42 are joined by thermal welding via the thermoplastic resin. In this case, the first exterior portion 41 and the second exterior portion 42 are electrically connected at the bent portion B.

[0048] 4 indicates the position of the joint portion J between the first exterior portion 41 and the second exterior portion 42. The width of the joint portion J in this second modified example is wider than the width of the joint portion J between the first exterior portion 41 and the second exterior portion 42 in the above embodiment.

[0049] 5 is a plan view of a battery 1 according to a third modification of the embodiment of the present disclosure. In this third modification, the first opening 41b, the second opening 42b, the first conductor 20, and the second conductor 30 extend in the Y direction from near the first corner C1 to near the second corner C2 defined by the first side S1 and the second side S2 in a plan view of the battery 1. In other words, the first conductor 20 and the second conductor 30 of this third modification are larger than the first conductor 20 and the second conductor 30 of the above embodiment. This reduces the current collection resistance of the first conductor 20 and the second conductor 30.

[0050] <Battery Pack 2> Fig. 6 is a top view of the battery pack 2 according to an embodiment of the present disclosure. Fig. 7 is a cross-sectional view of the battery pack 2 taken along line VII-VII shown in Fig. 6.

[0051] The battery pack 2 includes a housing 100 , a plurality of batteries 1 , a first positive terminal 110 , a second positive terminal 120 , a first negative terminal 130 , and a second negative terminal 140 .

[0052] The housing 100 is box-shaped and has an opening 100a. The housing 100 accommodates a plurality of batteries 1.

[0053] The battery 1 is configured similarly to the battery 1 in the above embodiment. The battery pack 2 includes three batteries 1. Specifically, the battery pack 2 includes a first battery 1c, a second battery 1d, and a third battery 1e. Note that the electrode body 11 is omitted from the battery 1 shown in FIG. 7 . Hereinafter, when the first battery 1c, the second battery 1d, and the third battery 1e are described without distinction, they will be simply referred to as "batteries 1."

[0054] The number of batteries 1 included in the battery pack 2 is three, but it goes without saying that the number is not limited to three. The number of batteries 1 included in the battery pack 2 is two or more. In other words, the battery pack 2 includes two batteries 1.

[0055] The first battery 1c, the second battery 1d, and the third battery 1e are stacked so as to be electrically connected in parallel. Specifically, the second main surface 42a of the first battery 1c and the first main surface 41a of the second battery 1d are in contact with each other and electrically connected, and the second conductor 30 of the first battery 1c and the first conductor 20 of the second battery 1d are in contact with each other and electrically connected.

[0056] Furthermore, in the second battery 1d and the third battery 1e, the second main surface 42a of the second battery 1d and the first main surface 41a of the third battery 1e come into contact with each other and are electrically connected, and the second conductor 30 of the second battery 1d and the first conductor 20 of the third battery 1e come into contact with each other and are electrically connected.

[0057] The first positive terminal 110 is strip-shaped. A first end of the first positive terminal 110 is electrically connected to the first conductor 20 of the first battery 1c. A second end of the first positive terminal 110 is located outside the housing 100. A spacer member 150 is disposed between the first positive terminal 110 and the exterior member 40 of the first battery 1c to electrically insulate the first positive terminal 110 from the exterior member 40.

[0058] The second positive terminal 120 is strip-shaped. A first end of the second positive terminal 120 is electrically connected to the second conductor 30 of the third battery 1e. A second end of the second positive terminal 120 is located outside the housing 100. In addition, a spacer member 160 that electrically insulates the second positive terminal 120 from the exterior member 40 of the third battery 1e is disposed between the second positive terminal 120 and the exterior member 40.

[0059] The first negative electrode terminal 130 is sheet-shaped and is in contact with and electrically connected to the first main surface 41 a of the first battery 1 c. The first negative electrode terminal 130 has an outer portion 131 located outside the housing 100.

[0060] The second negative electrode terminal 140 is sheet-shaped and is in contact with and electrically connected to the second main surface 42a of the third battery 1e. The second negative electrode terminal 140 has an outer portion (not shown) located outside the housing 100.

[0061] The battery pack 2 also has two plate members 170 that sandwich the multiple batteries 1 in the thickness direction (Z direction). The plate members 170 are electrically insulating and are made of materials such as elastic rubber and thermoplastic resin. By sandwiching the multiple batteries 1 between the two plate members 170, the contact state of the multiple batteries 1 can be stabilized. Spacers 180 are also disposed between the plate members 170 and the first positive terminal 110, and between the plate members 170 and the second positive terminal 120.

[0062] In the battery pack 2, the plurality of batteries 1 are simply electrically connected in parallel without using any additional components, and the battery pack 2 can therefore be made smaller.

[0063] The present disclosure may also be implemented as a combination of the following configurations.

[0064] (1) A battery comprising: an electrode assembly having a first electrode and a second electrode having a potential different from that of the first electrode; an exterior member including a first main surface having a first opening and a second main surface having a second opening, the exterior member housing the electrode assembly; and a first conductor and a second conductor electrically connected to the first electrode inside the exterior member, wherein the exterior member is electrically connected to the second electrode, the first main surface and the second main surface are on opposite sides of the electrode assembly, the first conductor has a first exposed portion exposed from the first opening, and the second conductor has a second exposed portion exposed from the second opening.

[0065] (2) The battery according to (1), further comprising a current collector joined to the first conductor and the second conductor and electrically connected to the first electrode.

[0066] (3) The battery according to (1) or (2), further including an insulating member disposed between the exterior member and the first conductor and sealing the first opening.

[0067] (4) The battery according to any one of (1) to (3), wherein the second electrode is electrically connected to the exterior member by contacting an inner surface of the exterior member.

[0068] (5) The battery according to any one of (1) to (4), wherein the first exposed portion overlaps the second exposed portion in a plan view of the first main surface.

[0069] (6) The battery according to any one of (1) to (5), wherein the first exposed portion has an exposed surface that is flush with the first main surface.

[0070] (7) The battery according to any one of (1) to (5), wherein the first exposed portion protrudes from the first opening.

[0071] (8) A battery pack comprising two batteries according to any one of (1) to (7), wherein the first main surface of a first battery of the two batteries is electrically connected to the second main surface of a second battery of the two batteries, and the first conductor of the first battery is electrically connected to the second conductor of the second battery.

[0072] REFERENCE SIGNS LIST 1 Battery 2 Battery pack 10 Electrode assembly 11 Electrode body 11a Positive electrode (first electrode) 11b Negative electrode (second electrode) 11c Separator 12 Current collector 20 First conductor 21 First exposed portion 21a First exposed surface (exposed surface) 30 Second conductor 31 Second exposed portion 40 Exterior member 41a First main surface 41b First opening 42a Second main surface 42b Second opening 50 First insulating member (insulating member) 60 Second insulating member

Claims

1. A battery comprising: an electrode assembly having a first electrode and a second electrode having a different potential from the first electrode; an exterior member that houses the electrode assembly and includes a first main surface having a first opening and a second main surface having a second opening; and a first conductor and a second conductor that are electrically connected to the first electrode inside the exterior member, wherein the exterior member is electrically connected to the second electrode, the first main surface and the second main surface are on opposite sides of the electrode assembly, the first conductor has a first exposed portion that is exposed from the first opening, and the second conductor has a second exposed portion that is exposed from the second opening.

2. The battery according to claim 1, further comprising a current collector joined to said first conductor and said second conductor and electrically connected to said first electrode.

3. The battery according to claim 1 or 2, further comprising an insulating member disposed between the exterior member and the first conductor and sealing the first opening.

4. The battery according to any one of claims 1 to 3, wherein the second electrode is electrically connected to the exterior member by contacting the inner surface of the exterior member.

5. The battery according to any one of claims 1 to 4, wherein, in a plan view of the first main surface, the first exposed portion overlaps with the second exposed portion.

6. The battery according to any one of claims 1 to 5, wherein the first exposed portion has an exposed surface that is flush with the first main surface.

7. The battery according to any one of claims 1 to 5, wherein the first exposed portion protrudes from the first opening.

8. A battery pack comprising two batteries according to any one of claims 1 to 7, wherein the first main surface of a first battery of the two batteries is electrically connected to the second main surface of a second battery of the two batteries, and the first conductor of the first battery is electrically connected to the second conductor of the second battery.

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