Battery module

Abstract

This battery module comprises: a plurality of first batteries that are connected with a first lead plate interposed therebetween; and a plurality of second batteries that are connected with a second lead plate therebetween. The first lead plate includes: a plurality of first lead plate terminal portions that are connected to the plurality of first batteries; a first body portion that is provided with the plurality of first lead plate terminal portions; and at least one first tab that is narrower than the first body portion, protrudes from an end portion of the first body portion toward the second lead plate, and is in contact with the second lead plate. The at least one first tab includes a welded portion that is welded to the second lead plate.

Description

Battery module

[0001] The present invention relates to a battery module.

[0002] In recent years, secondary batteries having a high energy density are environmentally friendly in that they do not generate by-products due to energy use, and thus battery modules are expected to be used as power sources for motor drives such as automobiles, or as household or industrial power sources.

[0003] Along with such changes in applications, battery modules are required to be able to handle higher voltages and larger currents, which has been solved by connecting a plurality of batteries in parallel and / or in series. As a result, changes have also occurred in their power transmission paths. In order to suppress heat generation, the cross-sectional area during transmission is increased to reduce the resistance, and instead of screwing that causes a change in resistance due to loosening of the screw and a decrease in the area of the joint part due to vibration, welding has become the mainstream for joining.

[0004] As an example of a battery module, for example, the battery module described in Patent Document 1 has been proposed. In the battery module described in Patent Document 1, a plurality of batteries are joined to one metal bus bar by welding.

[0005] Japanese Patent Application Laid-Open No. 2015-141,800

[0006] While secondary batteries are environmentally friendly in that they do not produce by-products due to energy use, in recent years, the high environmental load during the production of secondary batteries has been regarded as a problem.

[0007] However, in the conventional battery module described in Patent Document 1, since a plurality of batteries are welded and fixed with one bus bar, when a problem occurs in some batteries, it is necessary to replace the entire battery module.

[0008] The battery module of this disclosure comprises a plurality of first batteries connected via a first lead plate and a plurality of second batteries connected via a second lead plate. The first lead plate includes a plurality of first terminal portions connected to the plurality of first batteries, a first body portion on which the plurality of first terminal portions are provided, and at least one first tab having a width narrower than the first body portion, projecting from the end of the first body portion toward the second lead plate and in contact with the second lead plate. The at least one first tab includes a weld portion welded to the second lead plate.

[0009] This allows the battery to be easily removed from the battery module by detaching the tab portion.

[0010] Figure 1 is a perspective view showing a battery module according to an embodiment. Figure 2 is a perspective view of one battery holder removed from the battery module of Figure 1. Figure 3 is a disassembled perspective view of one battery holder removed from the battery module of Figure 1. Figure 4 is a disassembled view of one battery removed from the battery holder of Figure 3. Figure 5 is a perspective view showing the connection of adjacent first parallel units and second parallel units of the battery module of Figure 1. Figure 6 is a top view of the battery module of Figure 1 before the connection of the first parallel units and second parallel units. Figure 7 is a top view of the battery module of Figure 1 after the connection of the first parallel units and second parallel units. Figure 8 is a schematic diagram of the top view of Figure 3 before welding, cut at the portion through which the first tab passes. Figure 9 is a schematic diagram of the top view of Figure 3 after welding, cut at the portion through which the first tab passes. Figure 10 is a cross-sectional view of the top view of Figure 3, cut at the portion through which the positioning portion passes. Figure 11 is a schematic diagram of the case where the first tab of Figure 3 has an arch structure.

[0011] The form of this disclosure may be specified by the following configurations and features:

[0012] The embodiments of this disclosure will be described below with reference to the drawings. However, the embodiments shown below are illustrative examples for embodying the technical concept of this disclosure, and this disclosure is not limited to the following. Furthermore, this specification does not limit the components shown in the claims to the components of the embodiments. In particular, the dimensions, materials, shapes, relative arrangements, etc. of the components described in the embodiments are merely illustrative examples and are not intended to limit the scope of this disclosure to those components unless specifically stated otherwise.

[0013] Furthermore, the size and positional relationships of the components shown in each drawing may be exaggerated for clarity of explanation. In addition, in the following explanation, the same name and reference numeral indicate the same or identical components, and detailed explanations are omitted as appropriate. Moreover, each element constituting this disclosure may be configured such that multiple elements are made of the same component, with one component serving multiple elements, or conversely, the function of one component may be shared among multiple components.

[0014] Figure 1 is an external perspective view of a battery module 100 according to an embodiment of the present invention, and Figure 2 is an exploded perspective view of the plurality of battery holders 20 in Figure 1 when disassembled. As shown in Figures 1 and 2, the battery module 100 has a rectangular parallelepiped shape and is composed of a plurality of parallel units 10. The plurality of parallel units 10 consist of a battery holder 20, a plurality of batteries 30 housed inside each battery holder 20, and a plurality of lead plates 40 for connecting the plurality of batteries 30. Here, if the direction parallel to the long side of the battery module 100 is called the first direction X, and the direction parallel to the short side of the battery module 100 is called the second direction Y, then the plurality of parallel units 10 are arranged along the first direction X. The plurality of lead plates 40 are arranged on the upper surface of the battery holder 20 and electrically connect the plurality of batteries 30 housed inside the battery holder 20. In the example shown in this embodiment, the battery module 100 has 11 parallel units 10. Each parallel unit 10 houses multiple batteries 30 connected in parallel to each other. Multiple batteries 30 housed in adjacent parallel units 10 are connected in series.

[0015] The external shape of the power supply module is not limited to this embodiment, and can be any shape, such as a flat plate or a cube, depending on the configuration of the parallel unit.

[0016] Furthermore, the number of parallel units provided within the battery module is not limited to this embodiment and can be appropriately changed depending on the number of parallel and series connections of the batteries constituting the battery module. The number of parallel and series connections of the batteries constituting the battery module is adjusted according to the voltage and capacity in the intended design.

[0017] Figure 2 is a perspective view of one battery holder 20 removed from the battery module 100 in Figure 1, and Figure 3 is an exploded perspective view of one battery holder 20 removed from the battery module 100 in Figure 1. The multiple battery holders 20 shown in Figures 2 and 3 are composed of an upper fixing part 23, a lower fixing part 24, and multiple batteries 30. The upper fixing part 23 and the lower fixing part 24 sandwich the multiple batteries 30 arranged in the same orientation, so that the multiple batteries 30 are fixed inside the battery holder 20 with their positive terminals facing upwards.

[0018] As a result, the batteries in the battery holder are not fixed by irreversible methods such as adhesives, but are fixed by fitting them into each component, making it possible to easily disassemble the battery holder. In the example shown in this embodiment, within each battery holder 20, the batteries 30 are arranged in pairs along the first direction X of the battery module 100 and in groups of three along the second direction Y of the battery module 100.

[0019] In the aforementioned battery module, the battery holder is fixed by snapping it into place to facilitate easy disassembly and assembly, but this configuration is not the only option. Specifically, if disassembly of the battery holder is not required, the batteries within the holder can be fixed in place using an irreversible method such as adhesive. With this configuration, the battery holder can be treated as a single component, making it easy to remove from the battery module, which is particularly suitable when batteries are to be replaced in parallel units.

[0020] The orientation of the multiple batteries fixed inside the battery holder is not limited to this embodiment; they may be fixed so that the top surface of the battery module faces the negative terminal.

[0021] Furthermore, the number of batteries provided in the battery holder is not limited to this embodiment and can be changed as appropriate, adjusted according to the voltage and capacity of the intended design.

[0022] In this embodiment, cylindrical batteries are preferred for the multiple batteries 30. Figure 4 is a schematic diagram showing one battery 30 removed from among the multiple batteries 30 in the battery holder 20. The battery 30 shown in Figure 4 consists of a bottomed cylindrical outer casing 33 with one end open, and a sealing body 34 that seals the opening of the outer casing 33. The opening of the outer casing 33 of the cylindrical battery is sealed via the sealing body 34. In this embodiment, the negative electrode tab 36 of the electrode body is welded to the outer casing 33, and the positive electrode tab 37 of the electrode body is welded to the sealing body 34. With this configuration, the sealing body 34 is the positive electrode terminal, and the outer casing 33 is the negative electrode terminal. The first lead plate 41 is connected to the sealing body 34, which is the positive electrode terminal, and the second lead plate 42 is connected to the shoulder 35 of the outer casing 33, which is the negative electrode terminal. This allows the positive and negative terminals to be located on one side of the battery module, which improves the efficiency of the wiring route and makes it easier to achieve both miniaturization and high capacity in the battery module.

[0023] Figure 5 is an external perspective view of the first parallel unit 11 and the second parallel unit 12, which are adjacent parallel units 10 within the battery module 100. The first parallel unit 11 consists of a plurality of first batteries 31 fixed by an internal first battery holder 21 and a first lead plate 41. The first lead plate 41 is positioned on the upper surface of the first battery holder 21 and is connected to the first batteries 31 by a sealing body 34 which is the positive terminal portion. The second parallel unit 12 consists of a plurality of second batteries 32 fixed by an internal second battery holder 22 and a second lead plate 42. The second lead plate 42 is positioned on the upper surface of the second battery holder 22 and is connected to the second batteries 32 by the shoulder 35 of the outer casing 33 which is the negative terminal portion. The first lead plate 41 and the second lead plate 42 are positioned such that a portion of the first lead plate 41 overlaps on the second lead plate 42 and are electrically joined by welding. Multiple first batteries 31 are connected in parallel to each other by first lead plates 41, and multiple second batteries 32 are connected in parallel to each other by second lead plates 42. Multiple first batteries 31 and multiple second batteries 32 are connected in series to the first lead plates 41 and the second lead plates 42. As a result, the battery module can be disassembled and assembled via the first and second lead plates, and the output voltage is reduced when the series connection is disconnected, making it easier to handle.

[0024] Figure 6 is a top view of the battery module 100, an embodiment of the battery module, before the connection of the first parallel unit 11 and the second parallel unit 12, and Figure 7 is a top view of the battery module 100, an embodiment of the battery module, after the connection of the first parallel unit 11 and the second parallel unit 12. The first lead plate 41 shown in Figures 6 and 7 consists of a first main body portion 43, a first lead plate terminal portion 45 formed from the first main body portion 43, and a plurality of first tabs 47 that are thinner than the first main body portion 43. The first tabs 47 protrude from the end portion 43A of the first main body portion 43 toward the second lead plate 42. The width of the first tab 47 in the width direction perpendicular to the direction in which the first tab 47 protrudes is narrower than the width of the first main body portion 43 in the width direction. The first tab 47 has a near end 47P connected to the end portion 43A of the first main body portion 43, and a tip 47D on the opposite side of the near end 47P. Specifically, the first tab 47 protrudes from its near end 47P toward the tip 47D of the second lead plate 42. The first lead plate terminal portion 45 connects the first lead plate 41 to the positive terminal portion of the first battery 31. The second lead plate 42 is composed of a second main body portion 44, a second lead plate terminal portion 46 formed from the second main body portion 44, and a plurality of second tabs 48 that are thinner than the second main body portion 44. The second lead plate terminal portion 46 connects the second lead plate 42 to the negative terminal portion of the second battery 32. The first lead plate 41 and the second lead plate 42 are arranged such that the plurality of first tabs 47 and a portion of the first main body portion 43 overlap above the plurality of second tabs 48 and a portion of the second main body portion 44. Multiple first tabs 47 are joined to the second main body 44 by welding, and multiple second tabs 48 are joined to the first main body 43 by welding, thereby connecting the first battery 31 and the second battery 32 in series. In this embodiment, there are three first tabs 47 and two second tabs 48. As a result, the two lead plates 41 and 42 are fixed with sufficient force by welding. Furthermore, the two lead plates 41 and 42 are joined to each other at the tab portion. In detail, the first main body 43 of the first lead plate 41 is not welded to the second lead plate 42, and only the first tabs 47 are welded to the second lead plate. Therefore, the two lead plates 41 and 42 can be easily cut and removed from each other.Furthermore, since only the tab portion is cut after the two lead plates are cut, the reduction in overlapping area can be minimized, ensuring sufficient area for conductivity and suppressing the increase in heat generation associated with increased resistance.

[0025] The number of first tabs and second tabs is not limited to this embodiment and can be adjusted as appropriate depending on the purpose. For example, the number of first tabs and second tabs may be determined to match the number of fixing points that provide sufficient fixing force to securely fasten the two battery holders.

[0026] Furthermore, the first lead plate and the second lead plate only need to be joined by welding at least one first tab or second tab.

[0027] Furthermore, the first main body portion 43 may have an opening 50 in which the second tab 48 is exposed when viewed from above. This allows the second tab, visible through the opening, to serve as a marker for understanding the positional relationship between the first lead plate and the second lead plate, thereby improving the efficiency of alignment during the lead plate welding work for connecting the battery holder.

[0028] Furthermore, the second tab 48 can be cut from the opening 50. This makes it possible to easily cut the second tab, which is located on the back of the first main body and is difficult to cut, thus improving work efficiency.

[0029] Furthermore, as shown in Figure 6, the multiple first tabs 47 may be formed in the same direction toward the second lead plate from the first main body portion 43, and the multiple second tabs 48 may be formed in the same direction toward the first lead plate from the second main body portion 44. This eliminates the need to adjust the cutting direction to match the tab when cutting the tabs for battery holder replacement, thus improving work efficiency.

[0030] Furthermore, the direction in which the tabs are formed is not limited by this embodiment. Multiple first tabs 47 may be formed in different directions from the first main body 43 with respect to the second lead plate direction, and multiple second tabs 48 may be formed in different directions from the second main body 44 with respect to the first lead plate direction. As a result, a joint formed by tabs formed in different directions can fix the two lead plates against forces in a wider range of directions compared to a joint formed by tabs formed in the same direction. The direction in which the tabs are formed can be selected appropriately depending on the purpose and application of the battery module.

[0031] Figure 8 is a schematic diagram of the top view of Figure 7 cut at the point through which the first tab 47 passes, before welding, and Figure 9 is a schematic diagram of the top view of Figure 7 cut at the point through which the first tab 47 passes, after welding. According to Figures 8 and 9, the first tab 47 comprises a welded portion 60 and an unwelded portion 61 to the second main body 44. The welded portion 60 is welded to the second main body 44, while the unwelded portion 61 is not welded to the second main body 44. The area of ​​the welded portion 60 is smaller than the area of ​​the unwelded portion 61. The welded portion 60 is positioned on the tip 47D side of the first tab 47 than the unwelded portion 61. The thickness of the first tab 47 is determined so as to have a total heat capacity that allows welding to the second main body 44. The thickness of the first main body 43 is determined by the cross-sectional area required to transmit electric current. Furthermore, the welded portion 60 and the weld boundary portion 62 have a thinner thickness compared to the unwelded portion 61 due to evaporation during the welding process, and the change in thickness becomes greater as the first tab becomes thicker. The weld boundary portion 62 is the boundary between the welded portion 60 and the unwelded portion 61. As a result, when cutting the tab for battery holder replacement, the reduction in the area of ​​the tab after cutting is suppressed because there is a welded portion and an unwelded portion, making re-welding possible. In addition, although thick tabs are difficult to cut, the thickness of the welded portion and the weld boundary portion is thinner compared to the unwelded portion, especially for thick tabs. Therefore, even thick tabs can be cut efficiently.

[0032] Furthermore, the welded and unwelded portions only need to be formed on at least one first tab, and a similar structure may be formed on a second tab.

[0033] Furthermore, the thickness of the first tab is determined to have a total heat capacity that allows welding to the second main body, and the thickness of the first main body is determined by the cross-sectional area required to transmit current. Therefore, in this embodiment shown in Figure 6, the relative thicknesses of the first tab and the first main body are not limited, and the thickness of the first main body may be smaller than that of the first tab.

[0034] Figure 10 is a cross-sectional view including the positioning portion 52 provided on the joined first parallel unit 11 and second parallel unit 12 in this embodiment. The positioning portion 53 shown in Figure 10 is a protruding structure located on the upper surface of the first battery holder 21. The first lead plate 41 has a first hole 51 through which the positioning portion 53 passes, and similarly the second lead plate 42 has a second hole 52 through which the positioning portion 53 passes. After joining the first parallel unit 11 and the second parallel unit 12, the positioning portion 53 passes through the first hole 51 formed in the first lead plate 41 and the second hole 52 formed in the second lead plate 42. As a result, the positional relationship of the lead plates can be easily clarified based on the positioning portion, making it possible to improve the efficiency of the work of joining the battery holder.

[0035] Figure 11 shows a modified example of this embodiment, a schematic diagram of the part before welding, cut at the point through which the first tab 47 passes. In addition to the structure of the embodiment in Figure 8, the first tab 47 is composed of an arch structure 63 that is spaced apart from the second main body 44 at the non-welded portion 61, and a space that exists between the arch structure 63 and the second main body 44. As a result, when separating the tab for disassembling the battery holder, the tab can be easily separated by cutting it at the arch portion.

[0036] According to the technical concept of the present invention, it is possible to replace some of the batteries in a battery module without replacing the entire battery module by cutting the lead plates and removing and replacing the battery holder containing the faulty batteries. In particular, by cutting the tabs, it is possible to easily separate each lead plate while they are still welded to the battery cells, and deformation of the main body and non-welded parts of the lead plates during the replacement work can be prevented. If the main body and non-welded parts of the lead plates are deformed, it becomes difficult to re-weld the lead plates together after cutting the tabs, but according to the technical concept of the present invention, deformation of the main body and non-welded parts of the lead plates during the replacement work can be prevented, which also has the advantage of making it easy to reuse parts of the battery holder to be replaced. This battery module can be installed as a car battery and can also be widely used as a power source for household or industrial use.

[0037] The embodiments relating to this disclosure have been illustrated and described above. This disclosure is not limited to the embodiments described above, and modifications can be made by those skilled in the art without departing from the spirit of the invention within the scope of the rights claimed in the claims, and such modifications should not be understood individually from the technical idea or scope of the invention.

[0038] 100 Battery module 10 Parallel unit 11 First parallel unit 12 Second parallel unit 20 Battery holder 21 First battery holder 22 Second battery holder 23 Upper fixing part 24 Lower fixing part 30 Battery 31 First battery 32 Second battery 33 Outer casing 34 Sealing body 35 Shoulder 36 Negative electrode tab 37 Positive electrode tab 40 Lead plate 41 First lead plate 42 Second lead plate 43 First main body 44 Second main body 45 First lead plate terminal part 46 Second lead plate terminal part 47 First tab 48 Second tab 50 Opening 51 First hole 52 Second hole 53 Positioning part 60 Welded part 61 Non-welded part 62 Welded boundary part 63 Arch structure part X First direction Y Second direction

Claims

1. A battery module comprising: a plurality of first batteries; a plurality of second batteries; a first lead plate connected to the plurality of first batteries; and a second lead plate connected to the plurality of second batteries, arranged so as to partially overlap the first lead plate below, wherein the first lead plate includes: a plurality of first lead plate terminal portions connected to the plurality of first batteries; a first body portion on which the plurality of first lead plate terminal portions are provided; and at least one first tab having a width narrower than the first body portion, protruding from the end of the first body portion toward the second lead plate and in contact with the second lead plate, wherein the at least one first tab includes a welded portion welded to the second lead plate.

2. A battery module according to claim 1, wherein the at least one first tab further includes a first non-welded portion that overlaps with the second lead plate, and the battery module includes a welded portion located on the tip side of the at least one first tab relative to the first non-welded portion.

3. A battery module according to claim 2, wherein the area of ​​the first non-welded portion is larger than the area of ​​the welded portion.

4. A battery module according to claim 1, wherein the second lead plate partially overlaps the first lead plate below and includes a plurality of second lead plate terminal portions to which the plurality of second batteries are connected, a second body portion to which the plurality of second lead plate terminal portions are provided, and at least one second tab having a width narrower than the second body portion, protruding from the end of the second body portion toward the first lead plate and in contact with the first lead plate, wherein the at least one second tab includes a welded portion welded to the first lead plate.

5. A battery module according to claim 4, wherein the first lead plate includes a welded portion with the second tab, the second lead plate includes a welded portion with the first tab, and the first lead plate and the second lead plate are joined to each other by welding by the first tab and the second tab.

6. A battery module according to claim 4, wherein the first lead plate is disposed on the second lead plate, and the first lead plate includes an opening through which at least one second tab of the second lead plate is exposed.

7. A battery module according to claim 2, wherein the first non-welded portion includes an arch structure that is spaced apart from the second lead plate, and the arch structure forms a space between itself and the second lead plate.

8. A battery module according to claim 1, wherein the at least one first tab is a plurality of first tabs, and the plurality of first tabs protrude in the same direction.

9. A battery module according to claim 1, comprising a first tab which is thinner in thickness than the first main body portion of the first lead plate.

10. The battery module according to claim 4, wherein the battery module further comprises: a first battery holder for housing the plurality of first batteries; a first parallel unit including the first battery holder and the first lead plate; a second battery holder for housing the plurality of second batteries; and a second parallel unit including the second battery holder and the second lead plate, wherein the second parallel unit is configured to be separable from the first parallel unit.

11. A battery module according to claim 10, wherein the plurality of first batteries are connected in parallel by the first lead plate, the plurality of second batteries are connected in parallel by the second lead plate, and the plurality of first batteries and the plurality of second batteries are connected in series by the at least one first tab and the at least one second tab.

12. The battery module according to claim 10, wherein the battery module further includes a projection on the upper surface of the first battery holder, the first lead plate includes a first hole through the projection, the second lead plate includes a second hole through the projection, and the positioning portion is configured such that the projection penetrates the first hole and the second hole.

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