JP7848741B2 - Battery modules and battery packs - Google Patents

Description

This invention relates to a battery module and a battery pack.

Patent Document 1 describes a battery pack in which spacers are placed between multiple batteries. This document also describes a spacer constructed by placing a pair of resin plates on either side of a corrugated spring made of a metal material. This spacer functions as a passage for a cooling medium and also undergoes elastic deformation in response to the deformation of the batteries.

Japanese Patent Publication No. 2000-048867

However, when a refrigerant flow path is formed using a corrugated spring and a pair of plate materials, as described in Patent Document 1 above, the entire spacer is displaced due to the expansion and contraction of the battery cells during charging and discharging. Therefore, localized bending stress is likely to occur at the connection points between the spacer and the refrigerant piping due to variations in battery cell size. Thus, the above-mentioned prior art has room for improvement in this respect.

Considering the above facts, the present invention aims to provide a battery module and battery pack equipped with a cooler that can suppress the generation of localized bending stress due to variations in battery cell size.

The battery module according to claim 1 comprises a plurality of battery cells arranged in a line along a first direction and constrained from one another by a predetermined restraining load applied along the first direction, and a cooler disposed between the battery cells, wherein the cooler includes a first outer casing material and a second outer casing material stacked in the first direction, and comprises a cooler body formed in a bag shape by joining the outer peripheries of the first and second outer casing materials, and an elastic body disposed inside the cooler body, forming a flow path for a refrigerant that cools the battery cells together with the first and second outer casing materials.

The battery module described in claim 1 comprises a plurality of battery cells arranged in a line along a first direction, and a cooler positioned between the battery cells. The plurality of battery cells are constrained by a predetermined restraining load and are configured to be cooled by heat exchange with a refrigerant flowing through the inside of the cooler body. Here, the cooler body includes a first outer casing material and a second outer casing material stacked in the first direction, and is formed in a bag shape by joining the outer peripheries of the first and second outer casing materials. Furthermore, an elastic body is arranged inside the cooler body, and the elastic body, together with the first and second outer casing materials, forms a flow path for the refrigerant. As a result, even if variations in battery cell size occur due to expansion and contraction of the battery cells during charging and discharging, the cooler body and the internal elastic body deform in accordance with the displacement of the battery cells. Consequently, the generation of localized bending stress in the cooler is suppressed.

The battery pack according to claim 2 is a battery pack comprising a plurality of battery modules according to claim 1, wherein the plurality of battery modules include a first battery module and a second battery module adjacent to each other along a second direction perpendicular to the first direction, and between the first battery module and the second battery module, there are connection ends of the cooler body protruding from the first battery module and the second battery module, and a connecting member connecting these connection ends along the second direction, so that the refrigerant supplied to the cooler body of the first battery module is supplied to the cooler body of the second battery module via the connecting member.

The battery pack described in claim 2 includes a first battery module and a second battery module as a plurality of battery modules. The first battery module and the second battery module are adjacent to each other along a second direction perpendicular to the first direction. Furthermore, the connection ends of the cooler bodies protruding from the first battery module and the second battery module are connected via a connecting member, and the refrigerant supplied to the cooler body of the first battery module is supplied to the cooler body of the second battery module via the connecting member. As a result, in a battery pack comprising a plurality of battery modules, the cooler bodies are not arranged across the battery modules, and even if the relative positions of each battery module are displaced due to variations in battery cell size, the generation of local bending stress in the cooler between the battery modules is suppressed.

The battery pack according to claim 3, in the configuration according to claim 2, has the connecting member extending along the first direction, and connecting the connecting ends of the plurality of cooler bodies of the first battery module to the connecting ends of the plurality of cooler bodies of the second battery module.

In the battery pack described in claim 3, a connecting member extends along a first direction, and the connecting ends of the multiple cooler bodies of the first battery module and the connecting ends of the multiple cooler bodies of the second battery module are connected via this connecting member. As a result, the refrigerant that has flowed through the multiple cooler bodies on the first battery module side merges at the connecting member before being supplied to the multiple cooler bodies on the second module side. This suppresses temperature variations in the refrigerant supplied to the multiple coolers on the second battery module side, thereby improving cooling performance.

The battery pack according to claim 4, in the configuration according to claim 3, has the connecting member having the connecting end protruding from the first battery module and the connecting end protruding from the second battery module alternately connected along the first direction.

In the battery pack described in claim 4, the connecting member has connecting ends protruding from the first battery module and connecting ends protruding from the second battery module, alternately connected along the first direction. This allows the width of the connecting member to be shortened along the second direction, thereby increasing the heat exchange efficiency of the refrigerant when the refrigerant that has flowed through the multiple coolers on the first battery module side is merged at the connecting member. As a result, temperature variations in the refrigerant supplied to the multiple coolers on the second battery module side via the connecting member are further suppressed. Furthermore, by shortening the distance between battery modules along the second direction, the battery pack can be miniaturized.

As described above, according to the present invention, in a battery module and battery pack equipped with a cooler, it is possible to suppress the generation of localized bending stress in the cooler due to variations in the size of the battery cells.

This is a plan view from above of a battery pack equipped with a battery module according to the first embodiment. This is a partially enlarged cross-sectional view of a battery pack showing an enlarged view of the battery module according to the first embodiment. This is a cross-sectional view of the cooler, showing the state when cut along line 3-3 in Figure 2. This is a partial plan view showing an enlarged view of the connecting member shown in Figure 1. This is an enlarged side view showing the battery module according to the second embodiment. This is a plan view showing an enlarged view of the battery module according to the second embodiment.

<First Embodiment>
The first embodiment of the present invention will be described below with reference to Figures 1 to 4. Arrow D1 shown in each figure indicates a first direction of the battery module 20, and arrow D2 indicates a second direction of the battery module 20. The second direction D2 is perpendicular to the first direction D1.

Figure 1 shows a plan view of a battery pack 10 comprising multiple battery modules 20. As shown in this figure, the battery pack 10 is composed of a box-shaped case 12 and multiple battery modules 20 housed inside the case 12. The case 12 is formed by stacking a box-shaped lower case 14, which opens upwards, and a box-shaped upper case 16, which opens downwards, in the vertical direction. Furthermore, the case 12 is formed as a hollow, sealed box-shaped container by joining the outer periphery of the lower case 14 and the upper case 16 by lamination.

(Battery module)
The battery module 20 comprises a plurality of battery cells 22 arranged in a line along a first direction D1, and a cooler 30 positioned between the battery cells 22.

The battery cell 22 can be any type of secondary battery, but as an example, it is a lithium-ion secondary battery, and is composed of a positive electrode layer, a solid electrolyte layer, and a negative electrode layer (not shown) stacked to form an all-solid-state battery element. The positive electrode layer, solid electrolyte layer, and negative electrode layer of the battery cell 22 are housed in a rectangular box-shaped battery case 24 (see Figure 2), with the second direction D2 as the longitudinal direction and the first direction D1 as the short direction in a plan view. The battery case 24 may be made of resin or metal. Furthermore, the battery case 24 may have a laminated exterior.

A single battery module 20 is constructed by arranging battery cells 22 and coolers 30 alternately along a first direction D1. End plates 26, acting as restraining members, are positioned on both sides of the first direction D1 of a single battery module. The number of battery cells 22 incorporated into a single battery module 20 is not particularly limited, but in this embodiment, three battery cells 22 are arranged side-by-side along the first direction D1.

One battery module 20 is constrained by a predetermined restraining load along a first direction D1. This restraining load is applied by end plates 26 positioned between the cooler 30 and the side walls of the case 12 on both sides of the battery module 20 in the first direction D1.

Each battery cell 22 is subjected to a restraining load from the end plate 26, causing the side surface 24A of the battery case 24 facing the first direction D1 to contact the cooler 30. This allows heat exchange to occur between the coolant (omitted) circulating inside the cooler 30 and the battery cell 22. The cooler 30 enables cooling of the battery cell 22 when it generates heat during charging, etc. Conversely, in extremely low-temperature environments, it allows the battery cell 22 to heat up.

(cooler)
Figure 2 shows a battery cell 22 and a cooler 30 arranged along the side surface 24A of the battery cell 22. Figure 3 shows a cross-section of the cooler cut along the line 3-3 in Figure 2. As shown in this figure, the cooler 30 is composed of a cooler body 32 formed in the shape of a bag and an elastic body 40 arranged inside the cooler body 32.

The cooler body 32 includes a first outer casing material 34 and a second outer casing material 36 laminated in a first direction D1. The first outer casing material 34 and the second outer casing material 36 are substantially rectangular sheet-like members with the second direction D2 as the longitudinal direction and the first direction D1 as the thickness direction. The cooler body 32 is formed as a hollow bag-shaped sealed container by joining the outer peripheries of the first outer casing material 34 and the second outer casing material 36 by lamination. The first outer casing material 34 and the second outer casing material 36 are, for example, made of laminated casings used in pouch-type battery components, and are formed by resin coating a metal film. The metal film is made of aluminum film, stainless steel film, etc. The first outer casing material 34 and the second outer casing material 36 are deformable to follow the deformation of the side surface 24A of the battery cell 22 due to the load applied from the side surface 24A of the battery cell 22.

Furthermore, the cooler body 32 has a connecting end 32A protruding from one end and the other end along the second direction D2. A pipe-shaped refrigerant pipe 38 is connected to this connecting end 32A. The connecting end 32A is connected to a connecting member 50, which will be described later, via the refrigerant pipe 38.

The elastic body 40 has a plate-shaped base portion 42 and a plurality of elastic protrusions 44 protruding from the surface of the base portion 42. The elastic body 40 can be of any type as long as it is elastically deformable by the load applied from the side surface 24A of the battery cell 22, but as an example, it is made of molded rubber.

The base portion 42 is formed in a rectangular plate shape with the second direction D2 as the longitudinal direction and the first direction D1 as the short direction. Multiple elastic protrusions 44 are provided protruding from the first surface S1 and the second surface S2 of the base portion 42 facing the first direction D1, and each is formed in a cylindrical shape with the first direction D1 as the axial direction. The shape of the elastic protrusions may also be prismatic or corrugated.

As shown in Figure 3, the elastic projection 44 protruding from the first surface S1 of the base portion 42 facing the first exterior material 34 has its tip in contact with the first exterior material 34. On the other hand, the elastic projection 44 protruding from the second surface S2 of the base portion 42 facing the second exterior material 36 has its tip in contact with the second exterior material 36. In this way, within the cooler body 32, the inner surfaces of the first exterior material 34 and the second exterior material 36 are supported along the first direction D1 by the elastic projections 44 protruding from the elastic body 40.

With the above configuration, the elastic body 40, together with the first outer casing material 34 and the second outer casing material 36, forms a refrigerant flow path inside the cooler body 32. That is, as indicated by the arrows in Figure 2, the cooler 30 is configured such that refrigerant supplied to the interior from one connection end 32A of the cooler body 32 flows through the multiple elastic protrusions 44 and is discharged to the outside from the other connection end.

The refrigerant may be a gas or a liquid, but the refrigerant in this embodiment is a liquid refrigerant.

Returning to Figure 1, the battery modules 20 and connecting members 50 are arranged alternately along the second direction D2 within the case 12 of the battery pack 10. The number of battery modules 20 housed within the case 12 is not particularly limited, but in this embodiment, four battery modules 20 are arranged side-by-side along the second direction D2.

The connecting member 50 connects the coolers 30 incorporated in each battery module 20 between adjacent battery modules 20. The connecting member 50 is composed of a hollow, columnar member extending along the first direction D1.

As shown in Figure 4, the upper surface 50A of the connecting member 50 has a plurality of connection ports 52 that connect the inside and outside of the connecting member 50. The plurality of connection ports 52 are arranged at predetermined intervals along the first direction D1, and each connection port 52 is connected to the connection end 32A of the cooler body 32 via the refrigerant piping 38.

Between adjacent battery modules 20, the connecting end 32A of the cooler body 32 incorporated in each battery module 20 protrudes from the battery cell 22 of the battery module 20 and is positioned above the connecting member 50. The refrigerant piping 38 extends downward from the connecting end 32A and is connected to the connection port 52. Therefore, the connecting ends 32A protruding from the cooler 30 of the battery module 20 located downstream of the refrigerant flow path and the cooler 30 of the battery module 20 located upstream of the refrigerant flow path are connected by the connecting member 50 along the second direction D2.
In other words, the connecting member 50 is configured as a manifold that combines the refrigerant discharged from the connecting ends 32A of the multiple coolers 30 located on the downstream side of the flow path inside the connecting member 50, and then distributes it to the multiple coolers 30 located on the upstream side of the flow path.

Furthermore, the battery module 20 located upstream of the refrigerant flow path corresponds to the "first battery module" of the present invention, and the battery module 20 located downstream of the refrigerant flow path corresponds to the "second battery module" of the present invention.

Here, the multiple connection ports 52 of the connecting member 50 are alternately connected along the first direction D1 to the connection ends 32A of the coolers 30 located upstream of the refrigerant flow path and to the connection ends 32A of the coolers 30 located downstream of the refrigerant flow path. This shortens the width of the connecting member 50 along the second direction D2, facilitating mixing of the refrigerants merging from the downstream side of the flow path within the connecting member 50, thereby improving the heat exchange efficiency of the refrigerant. Therefore, variations in the temperature of the refrigerant supplied from the connecting member 50 to the upstream side of the flow path depending on the connection position can be suppressed. Furthermore, shortening the width of the connecting member 50 also shortens the distance between adjacent battery modules 20.

As shown in Figure 1, a first external pipe 60, to which refrigerant is supplied, is connected to a connecting member 50 located at the downstream end of the refrigerant flow path along the second direction D2. The refrigerant supplied from the first external pipe flows through the inside of the connecting member 50 along the first direction D1 and is supplied to multiple coolers 30 incorporated into the downstream battery module 20. Then, it rejoins at a connecting member 50 located between the battery modules 20 and is supplied from the connecting member 50 to multiple coolers 30 incorporated into the upstream battery module 20. By repeating this process, the refrigerant flows from the downstream to the upstream end of the flow path along the second direction D2, crossing multiple battery modules 20. Afterward, the refrigerant is discharged from the connecting member 50 located at the upstream end of the refrigerant flow path along the second direction D2, via the second external pipe 62 connected to the connecting member 50, to the outside of the battery pack 10.

(Mechanism of action and effect)
As described above, the battery module 20 according to this embodiment includes a plurality of battery cells 22 arranged in a line along a first direction D1, and a cooler 30 positioned between the battery cells 22. The plurality of battery cells 22 are constrained by a predetermined restraining load applied from the end plate 26, and are configured to be cooled by heat exchange with a coolant circulating inside the cooler body 32.

Here, the cooler body 32 includes a first outer casing material 34 and a second outer casing material 36 stacked in a first direction D1, and is formed in a bag shape by joining the outer peripheries of the first outer casing material 34 and the second outer casing material 36. Furthermore, an elastic body 40 is arranged inside the cooler body 32, and the elastic body 40, together with the first outer casing material 34 and the second outer casing material 36, forms a coolant flow path. As a result, even if variations in the size (thickness) of the battery cells 22 occur due to expansion and contraction of the battery cells 22 during charging and discharging, the cooler body 32 and the internal elastic body 40 deform in accordance with the displacement of the battery cells 22. As a result, the generation of localized bending stress in the cooler 30 is suppressed.

Furthermore, in adjacent battery modules 20, the connecting ends 32A of the cooler body 32 protruding from one battery module 20 (first battery module) and the other battery module 20 (second battery module) are connected via a connecting member 50. Therefore, the refrigerant supplied to the cooler body 32 of one battery module 20 is supplied to the cooler body 32 of the other battery module 20 via the connecting member 50. As a result, in a battery pack 10 comprising multiple battery modules 20, the cooler body 32 is not positioned across the battery modules 20. Therefore, even if the relative positions of each battery module 20 are displaced due to variations in the size (thickness) of the battery cells 22, the generation of localized bending stress in the cooler 30 between the battery modules 20 is suppressed.

Furthermore, a connecting member 50 extends along the first direction D1, and via this connecting member 50, the connecting ends 32A of the multiple cooler bodies 32 in the upstream battery module and the connecting ends 32A of the multiple cooler bodies 32 in the downstream battery module 20 are connected. As a result, the refrigerant that has flowed through the multiple cooler bodies 32 incorporated in the upstream battery module 20 merges at the connecting member 50 and is then supplied to the multiple cooler bodies 32 incorporated in the downstream battery module 20. This suppresses temperature variations in the refrigerant when it is supplied from the connecting member 50 to the multiple coolers 30 downstream, thereby improving cooling performance.

Furthermore, the connecting member 50 has connecting ends 32A protruding from the upstream battery module 20 and connecting ends 32A protruding from the downstream battery module 20, which are alternately connected along the first direction D1. This allows the width of the connecting member 50 to be shortened along the second direction D2, thereby increasing the heat exchange efficiency of the refrigerant when it flows through the multiple coolers 30 incorporated in the upstream battery module 20 and is merged at the connecting member 50. As a result, temperature variations in the refrigerant supplied to the multiple coolers downstream via the connecting member 50 are further suppressed. Additionally, shortening the distance between the battery modules 20 along the second direction D2 allows for miniaturization of the battery pack 10.

<Second Embodiment>
The battery module 70 according to the second embodiment will now be described with reference to Figures 5 and 6. Note that components identical to those in the first embodiment described above will be given the same numbers and their descriptions will be omitted. The battery module 70 according to this second embodiment is characterized in that a plurality of coolers 80 incorporated into the battery module 70 are connected along a first direction D1. Otherwise, it is the same as the first embodiment described above.

Figure 5 is a side view of the battery module 70, and Figure 6 is a top view of the battery module 70. As shown in these figures, the battery module 70 comprises a plurality of battery cells 22 arranged in a line along a first direction D1, and a cooler 80 positioned between the battery cells 22. The configuration of the battery cells 22 is the same as in the first embodiment described above, so a detailed explanation is omitted. The plurality of battery cells 22 in the battery module 70 are constrained by a restraining load applied from an end plate 26 (see Figure 1), which is not shown.

The cooler 80 is composed of a cooler body 82 formed in a bag shape and an elastic body 40 disposed inside the cooler body 82. It includes a first outer casing material 84 and a second outer casing material 86 laminated in a first direction D1 of the cooler body 82. The first outer casing material 84 and the second outer casing material 86 are substantially rectangular sheet-like members with the second direction D2 as the longitudinal direction and the first direction D1 as the thickness direction. In this embodiment, they are constructed with a laminated casing, similar to the first embodiment described above. The cooler body 82 is formed as a hollow bag-shaped sealed container by joining the outer peripheries of the first outer casing material 84 and the second outer casing material 86 by lamination.

The cooler body 82 has connecting ends 82A protruding from one end and the other end along the second direction D2. Here, the connecting end 82A located upstream of the refrigerant flow path is provided at the lower part of the cooler body 82. On the other hand, the connecting end 82A located upstream of the refrigerant flow path is provided at the upper part of the cooler body 82. Therefore, as indicated by the arrows in Figure 5, the refrigerant supplied to the lower part of the cooler body 82 flows from downstream to upstream and is discharged from the upper part of the cooler body 82. As a result, the refrigerant is distributed throughout the internal space of the cooler body 82, improving the heat exchange efficiency with the battery cell 22 and enhancing cooling performance.

As shown in Figure 6, a pipe-shaped refrigerant pipe 88 extending along the first direction D1 is connected to the connection end 82A. The refrigerant pipe 88 connects the connection ends 82A of two adjacent cooler bodies 82, with the battery cell 22 in between, along the first direction D1. The refrigerant pipe 88 consists, for example, of male and female joint members, with the male joint member connected to one connection end 82A and the female joint member installed on the other connection end 82A.

Furthermore, among the multiple coolers 80 incorporated into the battery module 70, the cooler 80 located at the end of the first direction D1 has a first external pipe 60 connected to its upstream connection end 82A for supplying refrigerant, and a second external pipe 62 connected to its downstream connection end 82A for discharging refrigerant. Therefore, as indicated by the arrows in Figure 6, the refrigerant supplied from the first external pipe 60 is supplied to the multiple cooler bodies 82 via the downstream refrigerant pipe 88, and then discharged to the outside through the second external pipe 62 via the upstream refrigerant pipe 88.

(Effects/Mechanisms)
The cooler 80 of the battery module 70 with the above configuration basically follows the configuration of the cooler 80 according to the first embodiment. Therefore, even in a battery module 70 equipped with a cooler 80, the same effect can be obtained in which the generation of localized bending stress due to variations in the size of the battery cells 22 can be suppressed.

Furthermore, in this embodiment, since adjacent cooler bodies 82 are connected along the first direction D1, the lamination direction of the first exterior material 84 and the second exterior material 86 coincides. As a result, the connection point between the cooler body 82 and the refrigerant piping 88 does not overlap with the joint between the exterior materials due to the lamination process, making it easier to connect the refrigerant piping 88.
[supplementary explanation]

The configurations of the first and second embodiments described above can be appropriately combined and modified without departing from the spirit of the present invention. Furthermore, the present invention is not limited to the embodiments described above. For example, in the first embodiment, the diameters of the multiple connection ports 52 formed in the connecting member 50 may be set to increase from the upstream side to the downstream side of the refrigerant flow path along the first direction D1. In this case, it is possible to suppress variations in the amount of refrigerant supplied between the cooler 30 located downstream of the first direction D1 and the cooler 30 located upstream.

Furthermore, from the viewpoint of suppressing variations in the amount of refrigerant supplied between the cooler 30 located downstream and the cooler 30 located upstream in the first direction D1, although not shown in the figures, the first external piping 60 may be connected to a connecting member 50 located in the center of the second direction D2 within the battery pack 10 case 12, thereby supplying refrigerant from the center of the second direction D2 to the coolers 30 on both sides. In this case, the second external piping 62 is connected to connecting members 50 located at both ends of the second direction D2 within the case 12.

Furthermore, while the second embodiment described above explains a configuration in which the cooler 80 is incorporated into a single battery module 70, the invention is not limited to this configuration. For example, the cooler 80 may be configured to cool multiple battery modules 70 arranged in a row along the second direction D2. In this case, each cooler 80 extends across the battery modules 70.

Furthermore, while the above embodiments involve laminating two sheet-like members, the first exterior material 34, 84 and the second exterior material 36, 86, and joining their outer peripheries, the configuration is not limited to this. The first exterior material 34, 84 and a portion of the second exterior material 36, 86 may be formed as a single sheet-like member, folded along predetermined fold lines and laminated, and a portion of the outer periphery joined to form a bag-shaped cooler body.

Furthermore, while the above embodiments describe the cooler bodies 32 and 82 and the elastic body 40 as separate components, the invention is not limited to this configuration. When the cooler body is molded from an elastic material, these components can be integrated. In this case, the cooler can be configured with a first exterior section (first exterior material) and a second exterior section (second exterior material) facing each other along the first direction D1, and an elastic section extending along the first direction D1, connecting the first and second exterior sections, and forming a refrigerant flow path together with the first and second exterior sections. With such a configuration, the cross-sectional shape when cut along the first direction D1 may be an eye-shaped or grid-shaped cross-section.

10 Battery packs 20 Battery modules (first battery module, second battery module)
22 Battery cell 30 Cooler 32 Cooler body 32A Connection end 34 First outer material 36 Second outer material 40 Elastic body 50 Connecting member 70 Battery module 80 Cooler 82 Cooler body 84 First outer material 86 Second outer material D1 First direction D2 Second direction

Claims (4)

A plurality of battery cells arranged in a line along a first direction and constrained from one another by a predetermined restraining load applied along the first direction,
The battery comprises a cooler positioned between the battery cells,
The aforementioned cooler is,
A cooler body comprising a first outer material and a second outer material stacked in the first direction, formed in a bag shape by joining the outer peripheries of the first and second outer materials,
An elastic body disposed inside the cooler body and, together with the first and second outer materials, forms a flow path for a refrigerant that cools the battery cell,
A battery module having A battery pack comprising a plurality of battery modules as described in claim 1,
The plurality of battery modules include a first battery module and a second battery module adjacent to each other along a second direction perpendicular to the first direction,
Between the first battery module and the second battery module, there are connection ends of the cooler body protruding from the first battery module and the second battery module, and a connecting member connecting these connection ends along the second direction.
The refrigerant supplied to the cooler body of the first battery module is supplied to the cooler body of the second battery module via the connecting member.
Battery pack. The connecting member extends along the first direction and connects the connecting ends of the plurality of cooler bodies of the first battery module to the connecting ends of the plurality of cooler bodies of the second battery module.
The battery pack according to claim 2. The connecting member has connecting ends protruding from the first battery module and connecting ends protruding from the second battery module alternately connected along a first direction.
The battery pack according to claim 3.