bipolar battery

Abstract

The present invention provides a bipolar battery that can prevent lateral displacement of the battery module caused by load input during loading, and can also suppress heat generation during potting material formation. [Solution] The bipolar battery 1 comprises a laminate 2 in which a plurality of battery modules 21 and coolers 22 are stacked alternately, a battery case 3 that houses the laminate 2, and a surrounding member 4 made of aluminum material that is positioned between the battery case 3 and the laminate 2 housed in the battery case 3 and surrounds the laminate 2. The surrounding member 4 has a contact wall portion 41 that is erected from the bottom surface of the battery case 3 and abuts against the side surface of the laminate 2, and a plurality of partition plate portions 42 that partition the space between the contact wall portion 41 and the inner wall of the battery case 3. The space partitioned by the partition plate portions 42 is filled with potting material 5.

Description

Technical Field

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[0005] ,<000​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​The present invention was made to solve these technical problems, and aims to provide a bipolar battery that can prevent lateral displacement of the battery module due to load input during collision, and can suppress heat generation during potting material formation. [Means for solving the problem]

[0007] The bipolar battery according to the present invention comprises a laminate in which a plurality of battery modules and a plurality of coolers are alternately stacked, a battery case housing the laminate, and a surrounding member made of aluminum material disposed between the battery case and the laminate housed in the battery case and surrounding the laminate, wherein the surrounding member has a contact wall portion erected from the bottom surface of the battery case and in contact with the side surface of the laminate, and a plurality of partition plate portions integrated with the contact wall portion and partitioning the space between the contact wall portion and the inner wall of the battery case, and the space partitioned by the partition plate portion is filled with potting material.

[0008] In the bipolar battery according to the present invention, the contact wall portion contacts the side surface of the laminate, thereby limiting the displacement of the laminate through surface contact. In addition, since potting material is filled into each space partitioned by the partition plate portion integrated with the contact wall portion, the cooperation between the potting material and the contact wall portion can prevent lateral displacement of the battery module caused by load input during collision. Furthermore, by providing the surrounding member, the volume of potting material (in other words, the amount of potting material used) can be reduced compared to when the surrounding member is not provided, thus reducing the heat generated during potting material formation. Moreover, since the heat generated during potting material formation can be released to the outside through the surrounding member made of aluminum material, heat generation during potting material formation can be suppressed. Furthermore, since the potting material is filled into each space partitioned by the partition plate portion, heat generated during the curing reaction is less likely to accumulate. As a result, lateral displacement of the battery module caused by load input during collision can be prevented, and heat generation during potting material formation can be suppressed.

[0009] In the bipolar battery according to the present invention, it is preferable that a plurality of through holes extending in the stacking direction of the laminate are formed in the contact wall portion, and that the potting material is filled into each through hole. In this way, by partitioning the potting material with through holes in addition to the partition plate portion, heat generation during the curing reaction is further prevented from accumulating. Moreover, by forming a plurality of through holes, the weight of the surrounding member can be reduced.

[0010] In the bipolar battery according to the present invention, the battery case is preferably widened from the bottom upwards, and the partition plate is preferably formed in a wedge shape that is widened from the bottom side upwards of the battery case so as not to create a gap between it and the inner wall of the battery case. In this way, the strength of the contact wall can be reinforced by the partition plate, thereby improving the effect of preventing lateral displacement of the battery module. [Effects of the Invention]

[0011] According to the present invention, it is possible to prevent lateral displacement of the battery module caused by load input during collision, and to suppress heat generation during potting material formation. [Brief explanation of the drawing]

[0012] [Figure 1] This is a perspective view showing a bipolar battery according to an embodiment. [Figure 2] This is a cross-sectional view along line AA in Figure 1. [Figure 3] This is an exploded perspective view showing the battery case, laminate, and surrounding components. [Modes for carrying out the invention]

[0013] Hereinafter, embodiments of the bipolar battery according to the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and their redundant descriptions are omitted.

[0014] Furthermore, to make the internal structure of the bipolar battery easier to understand, the battery case lid is omitted in each drawing. In addition, the following explanation will give an example in which the battery modules and coolers are stacked vertically, that is, an example in which the stacking direction is vertical.

[0015] Figure 1 is a perspective view showing a bipolar battery according to this embodiment, and Figure 2 is a cross-sectional view along line AA in Figure 1. The bipolar battery 1 according to this embodiment comprises a laminate 2 formed by stacking a battery module 21 and a cooler 22, a battery case 3 that houses the laminate 2, and a surrounding member 4 that is disposed between the battery case 3 and the laminate 2 housed in the battery case 3 and surrounds the laminate 2.

[0016] As shown in Figure 2, the laminate 2 is formed by alternately stacking multiple battery modules 21 and multiple coolers 22 along the vertical direction (stacking direction). The battery module 21 is a thin plate-shaped module in which multiple battery cells are stacked. Although not shown, each battery cell has a bipolar electrode, and current collectors and separators, each coated with positive and negative electrode active materials on both sides, are alternately stacked. Furthermore, each battery cell is formed in a structure that allows current to flow directly in the stacking direction of the bipolar electrode. In the battery module 21, the stacking direction of the battery cells and the direction in which the current flows are the same. Also, in this embodiment, the stacking direction of the battery cells and the stacking direction of the battery module 21 and the cooler 22 are the same.

[0017] The cooler 22 has a flattened box shape with a space for circulating refrigerant inside, and the refrigerant flowing inside absorbs heat from the battery module 21, thereby cooling the battery module 21. As shown in Figure 2, the cooler 22 is positioned between a pair of upper and lower battery modules 21 that are adjacent in the stacking direction, and is positioned to absorb heat from the pair of upper and lower battery modules 21. That is, the cooler 22 is sandwiched between the bottom surface of the upper battery module 21 and the top surface of the lower battery module 21 of the pair of upper and lower battery modules 21.

[0018] Although not shown, the cooler 22 has, for example, a first metal plate adhered to the bottom surface of the upper battery module 21, a second metal plate adhered to the top surface of the lower battery module 21, and a corrugated metal plate disposed between the first metal plate and the second metal plate to form a refrigerant flow path. The adhesion between the first metal plate and the upper battery module 21, and the adhesion between the second metal plate and the lower battery module 21 are each performed via a conductive adhesive.

[0019] Also, as shown in FIG. 2, since the sizes of the battery module 21 and the cooler 22 are different, when the battery module 21 and the cooler 22 are alternately stacked, a gap S occurs between the adjacent battery modules 21 in the vertical direction.

[0020] As in the example shown in FIG. 2, when the laminate 2 is formed by alternately stacking four battery modules 21 and three coolers 22, three gaps S are formed by the adjacent battery modules 21 and the cooler 22 disposed therebetween. That is, the gap S is formed by the bottom surface between the upper battery modules 21, the top surface of the lower battery module 21, and the side surface of the cooler 22 disposed between the upper battery module 21 and the lower battery module 21. This gap S extends, for example, in a direction orthogonal to the vertical direction (for example, the horizontal direction). And each gap S is filled with a potting material 5.

[0021] The battery case 3 has, for example, a box-shaped case body 31 that opens upward and a lid portion (omitted in the drawing) for closing the opening of the case body 31. The case body 31 widens upward from the bottom. And the lid portion and the case body 31 are fastened by bolts or the like in a state where the flange portions provided on each are overlapped. The battery case 3 is formed of, for example, an aluminum material or a zinc-plated steel sheet with electrodeposition coating.

[0022] The surrounding member 4 is formed of an aluminum material. As shown in FIG. 3, the surrounding member 4 has a rectangular tubular shape so as to surround the substantially rectangular parallelepiped-shaped laminate 2. More specifically, the surrounding member 4 has two relatively long long-side portions 4a and two relatively short short-side portions 4b so as to conform to the shape of the laminate 2. Each long-side portion 4a and each short-side portion 4b abut against four side surfaces of the laminate 2, respectively. The long-side portions 4a and the short-side portions 4b are formed separately and are connected to each other to constitute the surrounding member 4.

[0023] The short-side portion 4b and the long-side portion 4a have different lengths but the same structure. Therefore, hereinafter, the short-side portion 4b will be described as an example.

[0024] The short-side portion 4b of the surrounding member 4 has a contact wall portion 41 that stands upright from the bottom surface of the battery case 3 and abuts against the side surface of the laminate 2, and a plurality of partition plate portions 42 that are integrated with the contact wall portion 41 and partition the space between the contact wall portion 41 and the inner wall of the battery case 3.

[0025] The contact wall portion 41 is a hollow wall in which a plurality of through holes 43 are formed, and has a wall surface having the same size as the side surface of the laminate 2. The through holes 43 extend along the vertical direction and are arranged at equal intervals along the longitudinal direction of the contact wall portion 41 (see FIG. 3). The potting material 5 is filled in each through hole 43 (see FIG. 2).

[0026] The plurality (here, four) of partition plate portions 42 are arranged at equal intervals along the longitudinal direction of the contact wall portion 41. Each partition plate portion 42 is formed in a wedge shape that widens upward from the bottom side of the case body 31 so that no gap occurs between the partition plate portion 42 and the inner wall of the battery case 3 (more specifically, the inner wall of the case body 31). Specifically, as shown in FIG. 3, for example, when viewed from the longitudinal direction of the contact wall portion 41, the partition plate portion 42 has a right-angled triangular cross section, and its hypotenuse extends upward and outward from the bottom of the case body 31 following the shape of the inner wall of the case body 31.

[0027] In this embodiment, the partition plate portion 42 is formed lower than the contact wall portion 41. That is, the end of the wedge-shaped partition plate portion 42 is at the same position as the bottom surface of the contact wall portion 41, but the top of the partition plate portion 42 is at a lower position than the upper end surface of the contact wall portion 41. Alternatively, the partition plate portion 42 may be formed to have the same height as the contact wall portion 41.

[0028] As shown in Figures 1 and 2, the spaces between the contact wall portion 41 and the inner wall of the case body 31, which are separated by the partition plate portion 42, are filled with potting material 5. The potting material 5 is, for example, urethane resin, epoxy resin, or silicone resin.

[0029] In the bipolar battery 1 according to this embodiment, the surrounding member 4 made of aluminum material has a contact wall portion 41 that is erected from the bottom surface of the battery case 3 and abuts against the side surface of the laminate 2, and a plurality of partition plate portions 42 that partition the space between the contact wall portion 41 and the inner wall of the case body 31. By abutting against the side surface of the laminate 2, the contact wall portion 41 can limit the displacement of the laminate 2 through surface contact. In addition, since potting material 5 is filled into each space partitioned by the partition plate portion 42 integrated with the contact wall portion 41, the cooperation of the potting material 5 and the contact wall portion 41 can prevent lateral displacement of the battery module 21 caused by load input during collision.

[0030] In order to adequately support the laminate 2 during a collision, the material used to restrain the laminate 2 is required to have a certain degree of rigidity (strength). Furthermore, in order to prevent cracking during thermal cycles (e.g., -40°C to 65°C) that simulate market conditions, the material used to restrain the laminate 2 is also required to have a certain degree of toughness (resistance to cracking). The potting material 5 has excellent toughness, but lacks rigidity. On the other hand, the aluminum material has excellent rigidity. In this embodiment, as described above, the contact wall portion 41 made of the potting material 5 and the aluminum material is used in combination, and by utilizing the advantages of each material, it is possible to ensure the rigidity and toughness required to restrain the laminate 2 while preventing cracking of the potting material 5 caused by environmental changes such as thermal cycles.

[0031] Furthermore, by providing the surrounding member 4, the volume of potting material 5 (in other words, the amount of potting material 5 used) can be reduced compared to the case where the surrounding member 4 is not provided. That is, the volume of potting material 5 equivalent to that of the surrounding member 4 can be omitted. This makes it possible to reduce the heat generated during potting material formation. Moreover, since the heat generated during potting material formation can be released to the outside through the surrounding member 4 made of aluminum material, the heat generated during potting material formation can be suppressed. Furthermore, since the potting material 5 is filled into each space partitioned by the partition plate portion 42, the heat generated during the curing reaction is less likely to accumulate. As a result, lateral displacement of the battery module caused by load input during collision can be prevented, and the heat generated during potting material formation can be suppressed.

[0032] Furthermore, multiple through-holes 43 extending in the vertical direction are formed within the contact wall portion 41 of the surrounding member 4, and each through-hole 43 is filled with potting material 5. In this way, by partitioning the potting material with the through-holes 43 in addition to the partition plate portion 42, heat generation during the curing reaction is further prevented from accumulating. Moreover, the formation of multiple through-holes 43 makes it possible to reduce the weight of the surrounding member 4.

[0033] Furthermore, the partition plate portion 42 is formed in a wedge shape that widens upward from the bottom side of the case body 31, following the shape of the inner wall of the case body 31, so as not to create a gap between it and the inner wall of the case body 31. In this way, the strength of the contact wall portion 41 can be reinforced by the partition plate portion 42, thereby improving the effect of preventing lateral displacement of the battery module 21.

[0034] Although embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described above, and various design modifications can be made without departing from the spirit of the invention as described in the claims. [Explanation of symbols]

[0035] 1: Bipolar battery, 2: Laminate, 3: Battery case, 4: Surrounding member, 4a: Long side portion, 4b: Short side portion, 5: Potting material, 21: Battery module, 22: Cooler, 31: Case body, 41: Contact wall portion, 42: Partition plate portion, 43: Through hole, S: Gap

Claims

1. A laminate in which multiple battery modules and multiple coolers are stacked alternately, A battery case housing the aforementioned laminate, A surrounding member made of aluminum material is disposed between the battery case and the laminate housed in the battery case, and surrounds the laminate. Equipped with, The surrounding member has a contact wall portion that is erected from the bottom surface of the battery case and abuts against the side surface of the laminate, and a plurality of partition plate portions that are integrated with the contact wall portion and partition the space between the contact wall portion and the inner wall of the battery case. A bipolar battery characterized in that the space partitioned by the partition plate is filled with potting material.

2. Multiple through holes extending in the stacking direction of the laminate are formed within the aforementioned contact wall portion. The bipolar battery according to claim 1, wherein each through-hole is filled with the potting material.

3. The aforementioned battery case is widened from the bottom upwards, The bipolar battery according to claim 1 or 2, wherein the partition plate portion is formed in a wedge shape that widens upward from the bottom side of the battery case so as not to create a gap between it and the inner wall of the battery case.

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