Battery pack

Abstract

To provide a battery pack capable of suppressing deflection and twisting of a battery module in all directions without applying a load to a secondary battery cell.SOLUTION: A battery pack 100 according to the present invention includes a laminate 101 of a plurality of solid battery cells, end plates 102 connected to both ends of the laminate 101 in a stacking direction L, a first wall member 104 connected to each end plate 102 at both ends via a first self-centering mechanism 103A, and a support member 106 that supports the first wall member 104, the first self-centering mechanism 103A includes a spherical member 107, and two plate-like members 108 that can slide on a surface of the spherical member 107, and one plate member 108 is connected to the end plate 102, and the other plate member 108 is connected to the first wall member 104.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] In recent years, research and development have been conducted on secondary batteries that contribute to energy efficiency in order to enable more people to access affordable, reliable, sustainable, and advanced energy. In vehicles developed in recent years, battery modules that make up general electronic devices are installed in the form of battery packs attached to the vehicle.

[0003] The following problems exist in battery packs equipped with secondary battery cells. In a battery pack mounted on a vehicle, the battery module pressurized by the vibration of the vehicle is likely to bend and twist, and the secondary battery cells that make up the battery module may be damaged.

[0004] Patent Document 1 discloses a technique for suppressing the occurrence of bending even when a laminate of secondary battery cells constituting a battery module (battery stack) is pressurized in the stacking direction. This technique is realized by providing an inclination on the surface of the claw member that presses both ends of the laminate and absorbing the expansion on the pack side of the laminate.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the technology described in Patent Document 1, the bending that protrudes towards the pack side of the battery module is forcibly suppressed. As a result, a large load is placed on the secondary battery cells that make up the battery module, and there is a risk that the secondary battery cells will be damaged. Furthermore, while the technology in Patent Document 1 can suppress the bending that protrudes towards the pack side of the battery module, it is difficult to suppress the bending on other sides.

[0007] This invention has been made in view of the above circumstances, and aims to provide a battery pack that can suppress bending and twisting of the battery module in all directions without putting a load on the secondary battery cells. This will ultimately contribute to energy efficiency. [Means for solving the problem]

[0008] To solve the above problems, the present invention employs the following means.

[0009] (1) A battery pack according to one aspect of the present invention comprises a stack of a plurality of solid battery cells, end plates connected to both ends of the stack in the stacking direction of the stack, first wall members connected to the end plates at both ends via a first self-aligning mechanism, and a support member that supports the first wall members, wherein the first self-aligning mechanism is composed of a spherical member and two plate-shaped members that can slide on the surface of the spherical member, one of the plate-shaped members being connected to the end plate and the other plate-shaped member being connected to the first wall member.

[0010] In this configuration, the stack of solid-state battery cells is fixed to fixed members such as the first wall member and support member via a first self-aligning mechanism. Therefore, since the stack is in point contact with the fixed members, bending and wobbling of the stack caused by the expansion of the solid-state battery cells can be mitigated and suppressed in all directions.

[0011] Furthermore, with this configuration, pressure due to twisting and other forces transmitted from the fixed member side is equalized by passing through the first self-aligning mechanism, and equal pressure is applied to the laminate from all angles, thus achieving a state in which no large load is placed on the solid battery cells.

[0012] (2) In the battery pack described in (1) above, it is preferable that a protruding portion is provided between the end plate and the first wall member, protruding from the end plate or the first wall member.

[0013] With this configuration, by providing a protruding portion, it is possible to prevent the end plate from coming close to the first wall member when the laminate is deflected, and as a result, it is possible to prevent the laminate from deflecting too much.

[0014] (3) In the battery pack described in (2) above, it is preferable that the protrusion is provided on the side opposite to the support member, with the first self-aligning mechanism in between.

[0015] This configuration places the protrusion on the side that is expected to deflect the most relative to the other side, thus maximizing the effect of suppressing excessive deflection.

[0016] (4) In the battery pack described in either (2) or (3) above, it is preferable that the tip surface of the protrusion moves away from the rear end surface of the protrusion as it approaches the support member.

[0017] With this configuration, when the laminate flexes, the entire tip surface of the protrusion can be brought into surface contact with the end plate or first wall member adjacent to the protrusion. Because the contact area of ​​the protrusion with the end plate or first wall member can be increased, excessive flexing of the laminate can be suppressed in a stable state.

[0018] (5) In the battery pack described in any one of (2) to (4) above, it is preferable that the laminate and the end plate are spaced apart from the support member.

[0019] With this configuration, the waviness of the laminate due to volume expansion of solid-state battery cells is not hindered by contact with the support members. Therefore, the problem of stress being generated in the solid-state battery cells within the laminate and the resulting damage to the solid-state battery cells when the waviness of the laminate is hindered can be avoided.

[0020] (6) A battery pack according to another aspect of the present invention comprises a stack of a plurality of solid battery cells, second wall members connected to both ends of the stack in the stacking direction of the stack, end plates connected to the second wall members at both ends via a second self-aligning mechanism, a first wall member connected to the end plates, and a support member for supporting the first wall member, wherein the second self-aligning mechanism consists of a spherical member and two plate-shaped members that can slide on the surface of the spherical member, one of which is connected to the second wall member and the other plate-shaped member is connected to the end plate.

[0021] In this configuration, the stack of solid-state battery cells is fixed to the first wall member, support member, and other fixed members via a second self-aligning mechanism. Therefore, the stack is in point contact with the fixed members, which can mitigate and suppress bending and wobbling of the stack caused by the expansion of the solid-state battery cells in all directions.

[0022] Furthermore, with this configuration, pressure due to twisting and other forces transmitted from the fixed member side is equalized by passing through the second self-aligning mechanism, and equal pressure is applied to the laminate from all angles, thus achieving a state in which no large load is placed on the solid battery cells.

[0023] (7) In the battery pack described in (6) above, it is preferable that a protruding portion is provided between the second wall member and the end plate, protruding from the second wall member or the end plate.

[0024] According to this configuration, by providing the protruding portion, when the laminate is bent, it is possible to suppress the dispersion plate from approaching the end plate. As a result, it is possible to suppress the laminate from being bent too much.

[0025] (8) In the battery pack according to (7) above, it is preferable that the protruding portion is provided on the side opposite to the support member with the second self-aligning mechanism interposed therebetween.

[0026] According to this configuration, since the protruding portion is provided on the side where the largest bending is assumed relatively, the suppression effect of excessive bending can be maximized.

[0027] (9) In the battery pack according to any one of (7) or (8) above, it is preferable that the front end surface of the protruding portion moves away from the rear end surface of the protruding portion as it approaches the support member.

[0028] According to this configuration, when the laminate is bent, the entire front end surface of the protruding portion can be brought into surface contact with the dispersion plate or the end plate close to the protruding portion. Since the contact area of the protruding portion with respect to the dispersion plate or the end plate can be increased, excessive bending of the laminate can be suppressed in a stable state.

[0029] (10) In the battery pack according to any one of (6) or (9) above, it is preferable that the second wall member and the end plate are separated from the support member.

[0030] According to this configuration, the undulation of the laminate due to the volume expansion of the solid battery cell or the like is not hindered by contact with the support member. Therefore, when the undulation of the laminate is hindered, the problem that stress is generated in the solid battery cell in the laminate and the solid battery cell is damaged can be avoided.

Effects of the Invention

[0031] According to the present invention, it is possible to provide a battery pack that can suppress bending and twisting of the battery module in all directions without putting a load on the secondary battery cells, and thereby contribute to energy efficiency. [Brief explanation of the drawing]

[0032] [Figure 1] (a) A plan view of a battery pack according to the first embodiment of the present invention. (b) A magnified view of the battery pack of (a) near the self-aligning mechanism. [Figure 2] This is a cross-sectional view of the battery module in the same embodiment. [Figure 3] This is a cross-sectional view of a battery pack according to a second embodiment of the present invention. [Figure 4] This is a plan view of a battery pack according to a third embodiment of the present invention. [Figure 5] This is a cross-sectional view of the battery pack in the same embodiment. [Figure 6] This is a cross-sectional view of a battery pack according to Modification 1 of the same embodiment. [Figure 7] This is a cross-sectional view of a battery pack according to a modified example 2 of the same embodiment. [Figure 8] This is a cross-sectional view of a battery pack according to a modified example 3 of the same embodiment. [Figure 9] (a) A cross-sectional view of a battery pack according to the fourth embodiment of the present invention. (b) An enlarged view of the battery pack of (a) near the protruding portion. [Modes for carrying out the invention]

[0033] Hereinafter, a battery pack according to an embodiment to which the present invention is applied will be described in detail with reference to the drawings. Note that, for the sake of clarity, the drawings used in the following description may show enlarged versions of key features, and the dimensional ratios of each component may not be the same as those in reality. Furthermore, the materials, dimensions, etc., exemplified in the following description are merely examples, and the present invention is not limited to these; it can be implemented with appropriate modifications without altering its essence.

[0034] <First Embodiment> Figure 1(a) is a plan view of a battery pack 100 according to a first embodiment of the present invention. The battery pack 100 mainly comprises a stack 101 of a plurality of solid battery cells, a pair of end plates 102, a pair of self-aligning mechanisms 103, a pair of first wall members 104, a connecting member 105, and a support member 106. Figure 1(b) is an enlarged view of the battery pack 100 in Figure 1(a), showing the area near the first self-aligning mechanism 103.

[0035] The multiple solid battery cells (not shown) constituting the laminate 101 are assumed to be stacked in the Y direction. Each of the stacked multiple solid battery cells comprises a positive electrode current collector, a positive electrode active material, a solid electrolyte, a negative electrode active material, and a negative electrode current collector, and these are stacked in the Y direction so as to overlap directly or with other members in between.

[0036] One of a pair of end plates 102 is connected to each end of the stacked body 101 in the stacking direction L. One first end plate 102A is positioned to contact one end L1 of the solid battery cell 101 in the stacking direction L, and the other second end plate 102B is positioned to contact the other end L2 in the same stacking direction.

[0037] The restraining means (not shown) presses the multiple solid-state battery cells 101 in the stacking direction L from both ends L1 and L2 via the first end plate 102A and the second end plate 102B, thereby restraining the all-solid-state battery cells 101. The restraining means may be, for example, a band-shaped object (such as a restraining hoop) that surrounds the stacked all-solid-state battery cells 101, but other forms may also be used.

[0038] At each end of the laminate 101, the end plates 102 (102A, 102B) are connected to the first wall members 104 (104A, 104B) on the side opposite to the laminate 101 via a self-aligning mechanism 103 (first self-aligning mechanism 103A). In other words, end plate 102A is connected to first wall member 104A via first self-aligning mechanism 103A, and end plate 102B is connected to first wall member 104B via first self-aligning mechanism 103A. The first wall members 104A and 104B are each supported by a support member (pack) 106. The first wall members 104A and 104B may be connected via one or more connecting members 105.

[0039] The self-aligning mechanism 103 consists of a spherical member 107 and two plate-like members 108 (108A, 108B) that can slide on the surface of the spherical member 107. Plate-like member 108A is attached to the end plate 102, and plate-like member 108B is attached to the first wall member 104. Both plate-like members 108A and 108B have recesses on the surfaces that slide against the spherical member 107. A portion of the spherical member 107 is fitted into the recess of plate-like member 108A, and another portion of the spherical member 107 is fitted into the recess of plate-like member 108B. The spherical member 107 is held between plate-like members 108A and 108B.

[0040] Through the self-aligning mechanism 103, the end plate 102 and the laminate 101 are fixed in point contact with the first wall member 104. As a result, the pressure due to the twisting of the support member 106 is equalized in the self-aligning mechanism 103, and equal pressure is applied to the solid battery cells constituting the laminate 101 from all angles.

[0041] From the viewpoint of maintaining point contact between the end plate 102 and the laminate 101 and the first wall member 104, it is preferable that the spherical member 107 is made of a hard material such as high-speed steel or chromium-molybdenum steel, or, in the case of SUS, a material with hardness such as SUS440C or SUS630, and has a hardness equal to or greater than that of the first wall member. If the first wall member 104 is made of SUS304 (hardness 187: Vickers hardness HV equivalent) or aluminum alloy (duralumin) (hardness 155), it is preferable that the spherical member 107 has a hardness of 200 or more, exceeding those materials.

[0042] Figure 2 is a cross-sectional view of the battery pack 100 in Figure 1, cut along line AA. The laminate 101 undulates in all directions due to the volume expansion of the solid battery cells, etc. If this undulation is hindered, a load will be applied to the solid battery cells within the laminate 101, and there is a risk that the solid battery cells will be damaged. Therefore, in order to avoid hindering the undulation of the laminate 101, it is preferable that at least the laminate 101 and the end plate 102 are spaced apart from the support member 106.

[0043] As described above, in the battery pack 100 of this embodiment, the laminate 101 of solid battery cells is fixed to fixing members such as the first wall member and support member via the self-aligning mechanism 103. Therefore, since the laminate 101 is in point contact with the fixing member, bending and wobbling of the laminate 101 caused by the expansion of the solid battery cells 101 can be mitigated and suppressed in all directions.

[0044] Furthermore, pressure due to twisting and other forces transmitted from the fixed member side is equalized by passing through the self-aligning mechanism 103, and equal pressure is applied to the laminate 101 from all angles, thus achieving a state in which no large load is placed on the solid battery cells. This embodiment can contribute to energy efficiency by providing such a battery pack 100.

[0045] <Second Embodiment> Figure 3 is a plan view of a battery pack 110 according to a second embodiment of the present invention. In the battery pack 110, dispersion plates (second wall members) 111 (111A, 111B) are connected to both ends of the stacking direction of the solid battery cell laminate 101, and a self-aligning mechanism 103 (second self-aligning mechanism 103B) is installed between the dispersion plates 111 and the end plates 102 (102A, 102B). The end plates 102A and 102B are connected to first wall members 104A and 104B, respectively, which are supported by a support member 106. The dispersion plates 111 have the function of distributing the pressure from the self-aligning mechanism 103B so that it is applied evenly to the entire end face of the laminate 101. It is preferable that the laminate 101 and the dispersion plates 111 are spaced apart from the support member 106. The other configurations of the battery pack 110 are the same as those of the battery pack 100 described above, and it provides at least the same effects as the battery pack 100. The parts corresponding to the battery pack 100 are indicated by the same symbols.

[0046] This embodiment assumes a configuration in which end plates 102A and 102B are fixed to a support member 106 via first wall members 104A and 104B, and a laminated body (cell stack) 101 equipped with a self-aligning mechanism 103B at both ends is inserted between the fixed end plates 102A and 102B. With this configuration of battery pack 110, it is possible to manufacture the battery pack without requiring the operation of fastening the end plates 102 to the laminated body 101 while maintaining the load.

[0047] <Third Embodiment> Figure 4 is a plan view of a battery pack 120 according to a third embodiment of the present invention. Figure 5 is a cross-sectional view of the battery pack 120 of Figure 4 when cut along line AA. The battery pack 120 includes a projection 109 between the end plate 102 and the first wall member 104, which protrudes from either the end plate 102 or the first wall member 104. The other components of the battery pack 120 are the same as those of the battery pack 100, and it provides at least the same effects as the battery pack 100. Parts corresponding to those of the battery pack 100 are indicated by the same reference numerals.

[0048] The configuration of the protrusion 109 shown in Figures 4 and 5 is an example. The protrusion 109 is connected to only one of the end plate 102 and the first wall member 104, and is spaced apart from the other. Here, we illustrate a configuration in which the protrusion 109 has a rod-like (columnar, etc.) shape extending in the Y direction, with one end connected to the first wall member 104 and the other end spaced apart from the end plate 102. By providing the protrusion 109, when the laminate 101 flexes, it is possible to prevent the end plate 102 from coming close to the first wall member 104, and as a result, it is possible to prevent the laminate 101 from flexing too much.

[0049] The deflection of the laminate 101 is limited on the side of the support member 106, whereas on the opposite side of the support member 106, it can be unlimited because the surrounding area is open. Therefore, it is preferable to provide the protrusion 109 on the side where the deflection is relatively larger, and it is most preferable to provide it on the opposite side of the support member 106.

[0050] Figure 6 is a cross-sectional view of a battery pack 130 according to a modification 1 of the third embodiment. The protruding portion 109 may be connected to multiple locations between the first wall member 104 and the end plate 102. For example, as shown in Figure 6, if it is connected to two locations, on the opposite side (upper side) from the support member 106 and on the support member 106 side (lower side), it is possible to suppress not only excessive waviness due to expansion on the upper side of the laminate 101, but also excessive waviness due to expansion on the lower side.

[0051] Figure 7 is a cross-sectional view of a battery pack 140 according to Modification 2 of the third embodiment. The protruding portion 109 may not be connected to the first wall member 104, but may be connected to the end plate 102. For example, as shown in Figure 7, one end of the protruding portion 109 may be connected to the end plate 102, and the other end may be separated from the first wall member 104. Here, an example is given in which the protruding portion 109 is connected to only one place between the first wall member 104 and the end plate 102, but as with Modification 1, it may be connected to multiple places.

[0052] Figure 8 is a cross-sectional view of a battery pack 150 according to Modification 3 of the third embodiment. The self-aligning mechanism 103 only needs to be provided at two locations, one end L1 and the other end L2 of the laminate 101. For example, similar to the second embodiment, the self-aligning mechanism 103 (second self-aligning mechanism 103B) may be provided between the distribution plate 111 and the end plate 102. Here, the case in which the protrusion 109 is connected to only one location between the distribution plate 111 and the end plate 102 is illustrated, but similar to Modification 1, it may be connected to multiple locations.

[0053] <Fourth Embodiment> Figure 9(a) is a cross-sectional view of a battery pack 160 according to a fourth embodiment of the present invention. It shows a state in which the laminate 101 is bent due to volume expansion of the solid battery cells, and the upper end of the end plate 102 is close to the first wall member 104. Figure 9(b) is an enlarged view of the area near the protruding portion 109 of the battery pack 160 in Figure 9(a).

[0054] In the battery pack 160, the tip surface 109a of the protruding portion 109 that is close to (facing) the upper end of the end plate 102 or the first wall member 104 is inclined with respect to the normal direction (Z direction) of the surface of the support member 106. In other words, the tip surface 109a of the protruding portion 109 is inclined to move away from the rear end surface of the protruding portion 109 (the surface connected to the end plate 102 or the first wall member 104) as it approaches the support member 106. Here, the case in which the tip surface 109a of the protruding portion close to the end plate 102 is inclined is illustrated. The other configurations of the battery pack 160 are the same as those of the battery pack 120, and it provides at least the same effects as the battery pack 120. Parts corresponding to those of the battery pack 120 are indicated by the same reference numerals.

[0055] Because the surface 109a of the protruding portion is inclined in this way, the entire surface 109a of the protruding portion can be brought into surface contact with the surface 102a of the end plate, which rotates when the laminate 101 flexes. In other words, the contact area of ​​the protruding portion 109 with respect to the end plate 102 can be increased. Therefore, in this embodiment, compared to the case where only a part of the surface 109a of the protruding portion contacts the surface 102a of the adjacent end plate 102, excessive flexing of the laminate 101 can be suppressed in a more stable state.

[0056] In this embodiment, the orientation (inclination direction) of the surface 109a is set assuming a state in which the laminate 101 is deflected to the opposite side (upward) from the support member 106, as shown in Figure 9(a). A projection 109 with a different inclined surface may be used to assume a deflection to another side. For example, for deflection towards the support member (downward), a surface 109a that inclins to widen towards the laminate 101 as it moves away from the support member 106 is suitable, and a projection 109 having such a surface 109a may be used.

[0057] A protrusion 110 may be provided between the first wall member 104 and the end plate 102 on the side closer to the support member 106 than the first self-aligning mechanism 103A. In this case, it is possible to suppress the curvature (bending) of the laminate 101 such that the support member 106 side becomes convex, and it is possible to prevent the curved laminate 101 from contacting the support member 106 and damaging the cell side portions in the laminate 101. [Explanation of symbols]

[0058] 100, 110, 120, 130, 140, 150, 160... Battery packs 101...Laminate 102, 102A, 102B... End plates 102a... End plate surface 103...Self-centering mechanism 103A...First self-centering mechanism 103B...Second self-centering mechanism 104, 104A, 104B...First wall member 105... Connecting component 106...Support member 107...Spherical member 108, 108A, 108B... Plate-shaped members 109...Protrusion 109a...Tip surface of the protruding part 111, 111A, 111B...Dispersion plate (second wall member) L...Lamination direction L1... One end in the stacking direction L2...the other end in the stacking direction

Claims

1. A stack of multiple solid-state battery cells, End plates connected to both ends of the laminate in the stacking direction, The end plates at both ends are connected to first wall members via first self-aligning mechanisms, The system comprises a support member that supports the first wall member, The first self-aligning mechanism is composed of a spherical member and two plate-shaped members that can slide on the surface of the spherical member, with one plate-shaped member connected to the end plate and the other plate-shaped member connected to the first wall member. The end plate and the laminate are fixed to the first wall member in a point contact state via the first self-aligning mechanism. A battery pack characterized in that one end plate is arranged to contact one end of the solid battery cell in the stacking direction, and the other end plate is arranged to contact the other end of the solid battery cell in the stacking direction.

2. A laminate of multiple solid-state battery cells, End plates connected to both ends of the laminate in the stacking direction, The end plates at both ends are connected to first wall members via first self-aligning mechanisms, The system comprises a support member that supports the first wall member, The first self-aligning mechanism is composed of a spherical member and two plate-shaped members that can slide on the surface of the spherical member, with one plate-shaped member connected to the end plate and the other plate-shaped member connected to the first wall member. A battery pack characterized by having a protruding portion between the end plate and the first wall member, which protrudes from the end plate or the first wall member.

3. The battery pack according to claim 2, characterized in that the protruding portion is provided on the side opposite to the support member, with the first self-aligning mechanism in between.

4. The battery pack according to either claim 2 or 3, characterized in that the tip surface of the protrusion moves away from the rear end surface of the protrusion as it approaches the support member.

5. The battery pack according to any one of claims 1 to 4, characterized in that the laminate and the end plate are spaced apart from the support member.

6. A stack of multiple solid-state battery cells, Second wall members connected to both ends of the laminate in the stacking direction, End plates connected to the second wall members at both ends via a second self-aligning mechanism, The first wall member connected to the end plate, The system comprises a support member that supports the first wall member, The second self-aligning mechanism is composed of a spherical member and two plate-shaped members that can slide on the surface of the spherical member, with one plate-shaped member connected to the second wall member and the other plate-shaped member connected to the end plate. The second wall member and the laminate are fixed to the end plate in a point contact state via the second self-aligning mechanism. A battery pack characterized in that one of the second wall members is arranged to contact one end of the solid battery cell in the stacking direction, and the other of the second wall members is arranged to contact the other end of the solid battery cell in the stacking direction.

7. A laminate of multiple solid-state battery cells, Second wall members connected to both ends of the laminate in the stacking direction, End plates connected to the second wall members at both ends via a second self-aligning mechanism, The first wall member connected to the end plate, The system comprises a support member that supports the first wall member, The second self-aligning mechanism is composed of a spherical member and two plate-shaped members that can slide on the surface of the spherical member, with one plate-shaped member connected to the second wall member and the other plate-shaped member connected to the end plate. A battery pack characterized by having a protruding portion between the second wall member and the end plate, which protrudes from the second wall member or the end plate.

8. The battery pack according to claim 7, characterized in that the protrusion is provided on the side opposite to the support member, with the second self-aligning mechanism in between.

9. The battery pack according to either 7 or 8, characterized in that the tip surface of the protrusion moves away from the rear end surface of the protrusion as it approaches the support member.

10. The battery pack according to any one of claims 6 to 9, characterized in that the laminate and the second wall member are spaced apart from the support member.

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