Battery module

Abstract

This battery module 1 comprises: a plurality of divided holders 110 each accommodating one end of a plurality of battery blocks 23 and connecting in parallel at least a portion of a plurality of battery cells 20 included in each of the plurality of battery blocks 23 to each other; detachable bus bars 140 electrically interconnecting the plurality of divided holders 110 so as to connect in series the plurality of battery blocks 23; and one base holder 130 accommodating the other end of the plurality of battery blocks 23 so as to sandwich the plurality of battery blocks 23 with the plurality of divided holders 110.

Description

Battery module

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

[0002] Patent Document 1 discloses a battery module including a plurality of divided holders that each accommodate a plurality of battery cells. In the battery module, a plurality of battery cells are sandwiched between a positive electrode current collector plate and a negative electrode current collector plate and are electrically connected. Such a structure in which current collector plates are arranged so as to sandwich a plurality of battery cells is referred to as a double-sided current collection structure.

[0003] International Publication No. WO 2016 / 31208

[0004] Patent Document 1 discloses the concept of dividing a plurality of battery cells into groups for handling, but since the double-sided current collection structure is employed, the plurality of divided holders are integrally configured in a non-detachable manner. Therefore, it is difficult to replace only some of the divided holders, and there is room for improvement.

[0005] An object of the present disclosure is to provide a battery module in which partial replacement is easy.

[0006] The present disclosure provides a battery module including: a plurality of divided holders that each accommodate one end portion of a plurality of battery blocks and connect at least a part of a plurality of battery cells included in each of the plurality of battery blocks to each other in parallel; a detachable series connection portion that electrically connects between the plurality of divided holders so as to connect the plurality of battery blocks in series; and a single base holder that accommodates the other end portions of the plurality of battery blocks so as to sandwich the plurality of battery blocks together with the plurality of divided holders.

[0007] According to the present disclosure, a battery module in which partial replacement is easy can be provided.

[0008] A perspective view of a battery module according to an embodiment of the present disclosure. An exploded perspective view of the battery module. A perspective view of a battery cell. An exploded perspective view of a cell holder. A perspective view showing a divided holder. A first perspective view showing a current collection structure. A second perspective view showing the current collection structure. A third perspective view showing the current collection structure.

[0009] The following describes specific examples of this disclosure in detail based on the drawings. In the following description, terms indicating specific directions or positions may be used as needed. The use of such terms is for the purpose of facilitating the understanding of the invention by referring to the drawings, and the meaning of these terms does not limit the technical scope of this disclosure. Furthermore, parts with the same reference numerals appearing in multiple drawings indicate the same or equivalent parts or components. In addition, the embodiments shown below illustrate specific examples of the technical concept of this disclosure and do not limit this disclosure to those described below. Furthermore, the dimensions, materials, shapes, and relative arrangements of the components described below are intended as examples, and are not intended to limit the scope of this disclosure unless specifically stated otherwise. Also, the content described in one embodiment or example is applicable to other embodiments and examples. Finally, the size and positional relationships of the components shown in the drawings may be exaggerated to clarify the explanation.

[0010] Figure 1 shows a battery module 1 according to one embodiment of the present disclosure.

[0011] [Applications] The battery module 1 is applicable, for example, to emergency power supplies such as battery backup units (BBUs) and power supplies for the drive motors of electric vehicles. However, the applications of the battery module 1 are not particularly limited and it can be used as a power source for various other electrical devices.

[0012] [Exterior] The battery module 1 has a box-shaped exterior case 10 that extends in the longitudinal direction. A carrying handle 11 is attached to one end of the exterior case 10 in the longitudinal direction. Although not shown in detail, a power supply connector is provided at the other end of the exterior case 10 in the longitudinal direction.

[0013] [Overall Structure] Figure 2 shows an exploded perspective view of the battery module 1.

[0014] The battery module 1 has multiple battery cells 20, a cell holder 100 that encloses the multiple battery cells 20, a circuit board 30, a fan device 40, and a control device 50, all housed in an outer casing 10. The outer casing 10 is designed to be separated into upper and lower halves.

[0015] [Battery Cell] Figure 3 is a perspective view showing one of the multiple battery cells 20.

[0016] In this embodiment, each of the plurality of battery cells 20 is a cylindrical lithium-ion secondary battery. Each of the plurality of battery cells 20 has an outer casing 21 and a cap 22. The outer casing 21 is a bottomed cylindrical shape with an opening at one end in the axial direction DX (the upper end in Figure 3), and constitutes the negative electrode terminal. The cap 22 is positioned at one end in the axial direction DX, seals the opening of the outer casing 21 via an insulating material, and constitutes the positive electrode terminal (see the shaded area). That is, each of the plurality of battery cells 20 has a positive electrode terminal at the cap 22 in the center of the top, and negative electrode terminals at the side portion 21a, the bottom portion 21b, and the top edge portion 21c. The polarity may be configured in the opposite direction.

[0017] In this embodiment, the battery module 1 has 98 battery cells 20. The 98 battery cells 20 are divided into seven battery blocks 23A to 23G. Each of the seven battery blocks 23A to 23G contains 14 battery cells 20. However, these numbers can be appropriately changed depending on the required design. Hereafter, when describing the seven battery blocks 23A to 23G without distinction, they will simply be referred to as battery block 23.

[0018] [Cell Holder] Figure 4 shows a perspective view of the cell holder 100. Note that Figure 4 is shown upside down compared to Figure 2.

[0019] In this embodiment, the cell holder 100 has seven divided holders 110A to 110G and one base holder 130. However, the number of divided holders can be appropriately changed according to the required design. Hereafter, when describing the seven divided holders 110A to 110G without distinction, they will simply be referred to as divided holder 110.

[0020] Figure 5 is a perspective view showing the divider holder 110.

[0021] The split holder 110 accommodates one end (the upper end in Figures 4 and 5) of the battery block 23. The split holder 110 is made of an insulating material such as synthetic resin and is constructed, for example, by injection molding. The split holder 110 has a cell housing section 111 for housing one end of a plurality of battery cells 20 and a mounting section 112 for placing an insulating sheet 120 or the like.

[0022] The cell housing section 111 has a shape complementary to one end of the multiple battery cells 20. In the illustrated example, the cell housing section 111 holds 14 battery cells 20 arranged in a staggered pattern.

[0023] The mounting section 112 has an edge portion 113 that includes ribs 113a that rise from the cell housing section 111 on the opposite side from the multiple battery cells 20. Inside the ribs 113a, a current collection structure is formed, which includes an insulating sheet 120, several current collection plates, and several lead plates. The current collection structure will be described later, but in Figure 5 only the uppermost insulating sheet 120 is visible. The insulating sheet 120 is provided with a plurality of C-shaped gas vent holes 120a that function as gas vent valves.

[0024] Figure 6 is a first perspective view showing the current collection structure. Figure 6 shows the state after removing the insulating sheet 120, the current collection plate 125 (described later), and the current collection plate 129 (described later) from Figure 5.

[0025] In this embodiment, each of the multiple battery blocks 23 includes a first parallel block 24 (front left side in Figure 6) in which seven battery cells 20 are connected in parallel, and a second parallel block 25 (back right side in Figure 6) in which seven battery cells 20 are similarly connected in parallel. Each of the multiple divider holders 110 houses the first parallel block 24 and the second parallel block 25 side by side.

[0026] On the first parallel block 24 side, the lead plate 121, current collector plate 122, insulating sheet 123, lead plate 124, and current collector plate 125 (see Figure 5) are stacked from bottom to top in this order. Similarly, on the second parallel block side, the lead plate 124, current collector plate 126, insulating sheet 127, lead plate 128, and current collector plate 129 (see Figure 5) are stacked from bottom to top in this order. Note that the lead plate 124 is positioned across both the first parallel block 24 side and the second parallel block 25 side.

[0027] Figure 7 is a second perspective view showing the current collection structure. Figure 7 shows the current collection plate 122, insulating sheet 123, lead plate 124, and current collection plate 125 on the first parallel block 24 side, as well as the lead plate 124 and current collection plate 129 on the second parallel block 25 side, removed from Figure 6.

[0028] Figure 8 is a third perspective view showing the current collection structure. Figure 8 shows the current collection plate 126, insulating sheet 127, lead plate 128, and current collection plate 129 on the second parallel block 25 side removed from Figure 6.

[0029] Referring to Figure 7, the top edges (negative terminals) 21c of the multiple battery cells 20 in the first parallel block 24 are electrically connected to the lead plate 121. Here, the top edges (negative terminals) 21c and the lead plate 121 are welded together. This is also the case for the subsequent electrical connections between the lead plates 124 and 128 and the multiple battery cells 20. The lead plate 121 has tabs 121a that hang down from its side. The tabs 121a are provided with holes for fastening to the busbar 140 (see Figure 4), which will be described later, and screws 121b are attached to the holes.

[0030] Referring to Figure 8, the caps (positive terminals) 22 of the multiple battery cells 20 in the first parallel block 24 are electrically connected to the lead plate 124. The lead plate 124 is also electrically connected to the top edges (negative terminals) 21c of the multiple battery cells 20 in the second parallel block 25. Therefore, the first parallel block 24 and the second parallel block 25 are connected in series.

[0031] Referring to Figure 7, the caps (positive terminals) 22 of the multiple battery cells 20 of the second parallel block 25 are electrically connected to the lead plate 128. The lead plate 128 has tabs 128a that hang down from its side. The tabs 128a are provided with holes for fastening to the busbar 140 (see Figure 4), which will be described later, and screws 128b are attached to the holes.

[0032] Referring to Figure 4, the tab 121a on the first parallel block 24 side of one split holder (e.g., 110B) is electrically connected to the tab 128a on the second parallel block 25 side of another split holder (e.g., 110A) via a plurality of busbars (series connections) 140 that are reversibly joined. The tab 128a on the second parallel block 25 side of one split holder (e.g., 110B) is electrically connected to the tab 121a on the first parallel block 24 side of another split holder (e.g., 110C) via a plurality of busbars (series connections) 140 that are reversibly joined. Here, "reversibly joined" means a connection that can be easily released, and in this embodiment, the busbars 140 are configured to be detachable.

[0033] The busbar 140 is a conductive metal plate. The tabs 121a, 128a and the busbar 140 are fastened together by screws 121b, 128b. By releasing the fastenings by screws 121b, 128b and removing the busbar 140, the electrical connections between the multiple split holders 110 can be easily disconnected.

[0034] The base holder 130 accommodates the other ends (lower ends in Figure 4) of each of the multiple battery blocks 23. The base holder 130 is made of an insulating material such as synthetic resin and is formed, for example, by injection molding. The base holder 130 has a cell housing section 131 that accommodates the multiple battery blocks 23 together with the multiple divided holders 110. The base holder 130 has partition walls 132 between each of the divided holders 110.

[0035] The cell housing section 131 has a shape complementary to the other end (lower end in Figure 4) of the plurality of battery cells 20, and houses the other end of the plurality of battery cells 20. In the illustrated example, the cell housing section 131 is divided into seven housing areas 131a to 131g, corresponding to the seven divided holders 110A to 110G. The seven housing areas 131a to 131g are separated from each other by partition walls 132. The partition walls 132 are part of the base holder 130 and are integrally constructed with the cell housing section 131, not separate. In other words, the base holder 130 is a single component. Overall, the cell housing section 131 holds 98 battery cells 20 arranged in a staggered pattern. The base holder 130 has a length approximately equal to the total length of the plurality of divided holders 110A to 110G.

[0036] The base holder 130 does not have a structure that provides electrical connections to the multiple battery cells 20, and does not have conductive members such as lead plates or current collector plates. In other words, the battery module 1 of this embodiment employs a one-sided current collection structure in which the electrical connection structure is concentrated on the side of the multiple divided holders 110. In the one-sided current collection structure, the base holder 130 does not require complex fixing such as welding to the multiple battery cells 20. Therefore, the multiple battery cells 20 can be easily inserted into and removed from the base holder 130.

[0037] [Substrate] Referring to Figure 2, the substrate 30 is positioned adjacent to the cell holder 100. The substrate 30, together with the control device 50 described later, has various control functions.

[0038] [Fan device] Referring to Figure 2, the fan device 40 is located on one end of the cell holder 100 in the longitudinal direction (the left side in Figure 2). The fan device 40 has a fan that takes in outside air and blows it to the multiple battery cells 20 to air cool the multiple battery cells 20.

[0039] [Control device] Referring to Figure 2, the control device 50 is located on the other end of the cell holder 100 in the longitudinal direction (right side in Figure 2). The control device 50, together with the substrate, has various control functions.

[0040] [Functions and Effects] According to the battery module 1 of the above embodiment, the following functions and effects can be achieved.

[0041] Since the bus bar 140 and the divided holders 110 are joined by screws 121b and 128b and thus configured to be detachable, the connection between the plurality of battery blocks 23 can be released by removing the bus bar 140. Accordingly, each of the plurality of divided holders 110 can be easily taken out from the base holder 130. For example, when an abnormality is found only in some of the plurality of battery blocks 23, only the divided holder 110 that accommodates the abnormal battery block 23 can be taken out and replaced.

[0042] The structure with electrical connections exists only in the plurality of divided holders 110 and does not exist in the base holder 130. Therefore, by disconnecting the electrical connections of the plurality of divided holders 110, each divided holder 110 can be easily taken out.

[0043] Furthermore, since the cell holder 100 is divided, the welding of the lead plates 121, 124, 128 and the plurality of battery cells 20 can be performed in a small range for each of the plurality of divided holders 110. If the cell holder 100 is not divided, large-scale welding equipment is required. However, the division as in the present embodiment enables welding with small-scale welding equipment. Along with this, parallel welding processing is also enabled, and the lead time of the welding process can be shortened. Furthermore, constraints on finishing accuracy and processing accuracy that are required for large welding equipment can also be relaxed.

[0044] Furthermore, since the bus bar (direct current connection portion) 140 is attached to the side surface of each of the plurality of divided holders 110, it can be easily attached and detached.

[0045] Furthermore, since the plurality of bus bars 140 that are reversibly joined are adopted as the direct current connection portion between the plurality of divided holders 110, direct current connection can be realized with a simple configuration.

[0046] Furthermore, since the base holder 130 has partition walls 132 between the divided holders 110, improvement in safety accompanying enhanced insulation between the divided holders 110 can be realized.

[0047] Further, since ribs are provided on the edge 113 of the split holder 110, the strength of the single split holder is improved, and workability and safety during attachment and disassembly are improved.

[0048] Further, in each of the plurality of split holders 110, the plurality of battery cells 20 are connected in parallel and connected in series, so a high degree of design freedom regarding voltage, arrangement and the like can be secured. In addition, compared with a configuration in which series connection is not performed inside the plurality of split holders 110, the number of tabs 121a, 128a and bus bars 140 can be reduced, and the configuration can be simplified.

[0049] Although the embodiments have been described above, various modifications can be made to the above configuration within the scope of the spirit of the present disclosure.

[0050] In the above embodiment, the plurality of battery cells 20 are lithium-ion batteries, but they may be secondary batteries other than lithium-ion batteries, such as all-solid-state batteries.

[0051] In the above embodiment, an example has been described in which the series connection portion between the plurality of split holders 110 is the bus bar 140, but the series connection portion may be formed of other conductive members such as lead wires or a substrate.

[0052] This disclosure may include the following embodiments: (Embodiment 1) A battery module comprising: a plurality of divider holders each housing one end of a plurality of battery blocks and connecting at least a portion of a plurality of battery cells contained in each of the plurality of battery blocks in parallel with each other; a detachable series connection portion electrically connecting the plurality of divider holders to connect the plurality of battery blocks in series; and a base holder housing the other ends of the plurality of battery blocks so as to sandwich the plurality of battery blocks together with the plurality of divider holders. (Embodiment 2) The battery module according to Embodiment 1, wherein the series connection portion is mounted to connect the sides of the plurality of divider holders. (Embodiment 3) The battery module according to Embodiment 1 or 2, wherein the series connection portion includes a plurality of reversibly joined busbars. (Embodiment 4) The battery module according to Embodiment 3, wherein the plurality of reversibly joined busbars are fastened to the plurality of divider holders by screws. (Aspect 5) The battery module according to any one of aspects 1 to 4, wherein each of the plurality of battery blocks includes a first parallel block in which a plurality of battery cells are connected in parallel with each other and a second parallel block in which another plurality of battery cells are connected in parallel with each other, and each of the plurality of divider holders connects the first parallel block and the second parallel block in series. (Aspect 6) The battery module according to any one of aspects 1 to 5, wherein the base holder is made of an insulating material. (Aspect 7) The battery module according to any one of aspects 1 to 6, wherein the base holder includes a partition wall between adjacent divider holders. (Aspect 8) The battery module according to any one of aspects 1 to 7, wherein the plurality of divider holders include ribs on their edges.

[0053] 1 Battery module 10 Outer case 11 Handle 20 Battery cell 21 Outer can 21a Side 21b Bottom 21c Top edge 22 Cap 23, 23A-23G Battery block 24 First parallel block 25 Second parallel block 30 Circuit board 40 Fan device 50 Control device 100 Cell holder 110, 110A-110G Split holder 111 Cell housing 112 Mounting section 113 Edge 113a Rib 120 Insulating sheet 120a Gas vent hole 121 Lead plate 121a Tab 121b Screw 122 Current collector plate 123 Insulating sheet 124 Lead plate 125 Current collector plate 126 Current collector plate 127 Insulating sheet 128 Lead plate 128a Tab 128b Screw 129 Current collector plate 130 Base holder 131 Cell housing section 131a-131g Housing area 132 Partition wall 140 Busbar (DC connection section)

Claims

1. A battery module comprising: a plurality of divider holders, each housing one end of a plurality of battery blocks and connecting at least a portion of the plurality of battery cells contained in each of the plurality of battery blocks in parallel with one another; a removable series connection portion that electrically connects the plurality of divider holders so as to connect the plurality of battery blocks in series; and a base holder that houses the other ends of the plurality of battery blocks so as to sandwich the plurality of battery blocks together with the plurality of divider holders.

2. The battery module according to claim 1, wherein the series connection portion is attached to connect the sides of the plurality of divider holders.

3. The battery module according to claim 1 or 2, wherein the series connection portion includes a plurality of reversibly connected busbars.

4. The battery module according to claim 3, wherein the reversibly joined busbars are fastened to the plurality of split holders by screws.

5. The battery module according to claim 1 or 2, wherein each of the plurality of battery blocks includes a first parallel block in which a plurality of battery cells are connected in parallel with each other and a second parallel block in which another plurality of battery cells are connected in parallel with each other, and each of the plurality of divider holders connects the first parallel block and the second parallel block in series.

6. The battery module according to claim 1 or 2, wherein the base holder is made of an insulating material.

7. The battery module according to claim 1 or 2, wherein the base holder includes a partition wall between adjacent divider holders.

8. The battery module according to claim 1 or 2, wherein the plurality of divider holders include ribs on their edges.

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