Battery pack

Abstract

To provide a battery pack capable of suppressing intrusion of foreign matters such as dust into an inner space.SOLUTION: A battery pack has a battery cell, an external connection terminal 4, and a case that accommodates the battery cell and the external connection terminal 4. The case includes an upper case 21 and a lower case 22. An inner space of the case has: an accommodation region for accommodating the battery cell; and an accommodation region 222 for accommodating the external connection terminal 4. The lower case 22 has: a coating layer X that covers a lower part of the accommodation region 221; and a barrier 212 extending from an upper inner surface of the upper case toward the coating layer X and arranged between the battery cell and the external connection terminal 4. A tip of the barrier 212 is positioned so as to be in contact with the coating layer X. The external connection terminal 4 is connected with the battery cell via a circuit board 5 buried in the coating layer X at least below the barrier 212.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a battery pack in which battery cells are housed in a case. [Background technology]

[0002] Conventionally, battery packs house multiple battery cells in a case with a waterproof or dustproof structure, because the performance of the battery pack can be degraded if foreign matter such as dust enters the internal space of the battery pack from the outside.

[0003] Japanese Patent Application Laid-Open Publication No. 2004-203067 (Patent Document 1) discloses a battery pack in which a battery core pack containing multiple batteries is housed within a waterproof sheet in a sealed, waterproof structure. The battery pack includes a charging terminal and a discharging terminal connected to the battery core pack via lead wires. The waterproof sheet is cylindrical with openings at both ends, each of which leads to either a charging terminal or a discharging terminal. One opening of the waterproof sheet is provided with a retention welding portion that welds the waterproof sheet to prevent the battery core pack placed on the waterproof sheet from slipping out of the opening at one end, and a sealant is provided in the insertion gaps through which the charging terminal and discharging terminal are led out. This waterproof sheet is also thought to prevent foreign matter such as dust from entering the waterproof sheet. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6098254 [Patent Document 2] Japanese Patent Application Publication No. 8-153501 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the battery pack of Patent Document 1, there is a risk that the sealant may peel off from the waterproof sheet due to vibrations during use or transportation of the battery pack, and deterioration over time, allowing foreign matter such as dust to enter through the peeled gap.In addition, because the battery core pack itself housed in the waterproof sheet does not have a dustproof structure, foreign matter such as dust that gets into the waterproof sheet may adversely affect the battery performance of the battery core pack.

[0006] Therefore, an object of the present disclosure is to provide a battery pack that can prevent foreign matter such as dust from entering the internal space. [Means for solving the problem]

[0007] In order to solve the above problems, the present disclosure is configured as follows. That is, a battery pack according to the present disclosure may be a battery pack having battery cells, external connection terminals, and a case that accommodates the battery cells and the external connection terminals. The internal space of the case may have a first accommodation area that accommodates the battery cells and a second accommodation area that accommodates the external connection terminals. The case may have a first covering layer that covers a lower portion of the second accommodation area, and a first partition wall that extends from an upper portion of the internal space of the case toward the first covering layer and is disposed between the battery cells and the external connection terminals. An end of the first partition wall may be positioned so as to contact the first covering layer. The external connection terminals may be connected to the battery cells via connectors embedded in the first covering layer.

[0008] The connection portion may include a circuit board, and the first covering layer may be formed of a potting material that covers the circuit board.

[0009] The case may have a slit for connecting the external connection terminal to the outside, and the first partition wall may be disposed so as to surround the periphery of the external connection terminal excluding the slit and a portion below.

[0010] The first bulkhead may have a leg extending downward from its tip.

[0011] The case may further include a second covering layer covering a lower portion of the outer periphery of the first storage area, and a second partition wall extending from above the internal space of the case toward the second covering layer and extending from the first partition wall along the outer periphery of the internal space of the case. An end of the second partition wall may be positioned so as to contact the second covering layer. [Effects of the Invention]

[0012] The battery pack according to the present disclosure can prevent foreign matter such as dust from entering the internal space. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a perspective view showing a battery pack according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is an exploded view showing the structure of the battery pack shown in FIG. [Figure 3] 3 is a perspective view of the upper case shown in FIG. 1 as viewed from below. [Figure 4] FIG. 4 is a cross-sectional view of the battery pack shown in FIG. [Figure 5] FIG. 5 is a perspective view showing a modification of the battery pack shown in FIG. [Figure 6] FIG. 6 is a perspective view showing an upper case of a battery pack according to a second embodiment of the present disclosure. [Figure 7] FIG. 7 is a plan view showing the lower case of the battery pack of the second embodiment. [Figure 8] FIG. 8 is a cross-sectional view showing a battery pack according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] (First embodiment) A battery pack 1 according to a first embodiment of the present disclosure will be specifically described below with reference to Figures 1 to 5. As shown in Figure 1, the battery pack 1 includes a case 2. The case 2 includes an upper case 21 and a lower case 22.

[0015] The upper case 21 is made of synthetic resin and is formed in an inverted dish shape. As shown in FIG. 2, the upper case 21 has a shape of two rectangles, a large rectangle and a small rectangle, joined together in a plan view. The upper case 21 has a slit 211 for connecting the external connection terminal 4 to the outside. The slit 211 is formed in the portion of the upper case 21 that is formed in the small rectangle. Note that the shape of the case 2 is not limited to this, and the entire case may be rectangular in a plan view, or may be a polygonal, circular, or elliptical shape, as long as the internal space of the case 2 can form the housing areas 221 and 222, which will be described later.

[0016] The lower case 22 is made of synthetic resin and is formed in a dish shape. In a plan view, the lower case 22 has a shape consisting of two connected rectangles, a large rectangle and a small rectangle. The upper case 21 and the lower case 22 are fixed together with their outer peripheral edges aligned using screws α shown in FIG. 2. This forms an internal space in the case 2.

[0017] The internal space of the case 2 has a storage area 221 that stores the battery cells 3, and a storage area 222 that stores the external connection terminals 4 and the circuit board 5. The storage area 221 is an area surrounded mainly by the large rectangular portions of the upper case 21 and the lower case 22. The storage area 222 is an area surrounded mainly by the small rectangular portions of the upper case 21 and the lower case 22. The lower case 22 has a partition plate 223 between the storage area 221 and the storage area 222 to separate the lower parts of both areas.

[0018] The lower part of the housing area 222, i.e., the lower surface of the small rectangular portion of the lower case 22, is covered with a covering layer X. As will be described later (see FIG. 4), the circuit board 5 is embedded in the covering layer X. The covering layer X is, for example, a potting material that covers the circuit board 5.

[0019] As shown in FIG. 2 , the internal space of the case 2 accommodates the battery cells 3, external connection terminals 4, circuit board 5, and coating layer X, as well as lead wires 6. The lead wires 6 connect the battery cells 3 to the circuit board 5. The circuit board 5 and lead wires 6 connect the battery cells 3 to the external connection terminals 4. Therefore, the circuit board 5 and lead wires 6 function as a connection section. The lead wires 6 extend above the partition plate 223 and are connected to the circuit board 5. The battery cells 3 and external connection terminals 4 may be connected using only the lead wires 6. Therefore, the connection section may be composed of only the lead wires 6, without providing the circuit board 5. In other words, the battery cells 3, lead wires 6, and external connection terminals 4 may be connected in this order. The internal space of the case 2 accommodates metal connection pieces 7, but a detailed description of this will be omitted here.

[0020] The battery cells 3 are rechargeable lithium ion batteries. However, the battery cells 3 are not particularly limited as long as they are rechargeable secondary batteries.

[0021] The external connection terminal 4 inputs and outputs electric power to and from the battery pack 1. The external connection terminal 4 can be connected to the outside via a slit 211.

[0022] The circuit board 5 has a protection circuit that prevents overcharging and overdischarging of the battery cells 3. External connection terminals 4 and lead wires 6 are connected to the circuit board 5.

[0023] As shown in FIG. 3 , the upper case 21 has a partition wall 212. The partition wall 212 is disposed between the battery cells 3 and the external connection terminals 4 in the internal space of the case 2. Note that FIG. 3 is a perspective view of the upper case 21 as viewed from below, and therefore the following description of FIG. 3 will be upside down. That is, in FIG. 3 , the bottom is the top of the upper case 21, and the top is the bottom of the upper case 21. The partition wall 212 is disposed in the internal space of the case 2 from above to below the upper case 21, i.e., from the upper inner surface of the upper case 21 toward the surface of the coating layer X. The partition wall 212 is disposed in the internal space of the case 2 so as to surround the periphery of the external connection terminals 4 except for the slits 211 and the areas below the external connection terminals 4. Furthermore, terminal partition plates 213 are formed in the space enclosed by the partition wall 212 and the upper case 21, and are disposed to separate each of the external connection terminals 4. By disposing the partition wall 212 between the battery cell 3 and the external connection terminals 4 in this manner so as to surround the multiple external connection terminals 4, it is possible to more accurately separate the space within the internal space of the case 2 in which the external connection terminals 4 are disposed for connection to the outside from a sealed space that prevents the intrusion of foreign matter such as dust from the outside. Furthermore, by providing the terminal partition plate 213, it is possible to prevent short circuits that may occur due to contact between the external connection terminals 4. Furthermore, the partition wall 212 has legs 214 that extend downward from its tip. One or more legs 214 are provided at the tip of the partition wall 212.

[0024] As shown in FIG. 4 , in a cross-sectional view, the storage area 222 that stores the external connection terminals 4 is located to the right of the partition plate 223. Note that a storage area 221 (not specifically shown) that stores the battery cells 3 is located to the left of the partition plate 223. In the storage area 222, the partition wall 212 extends downward from the upper inner surface of the upper case 21, i.e., toward the covering layer X. The covering layer X is disposed so as to cover the lower portion of the storage area 221. The covering layer X is a potting material that protects the circuit board 5. The tip of the partition wall 212 contacts the covering layer X. This prevents dust and other foreign matter that has entered through the slits 211 from entering the internal space inside the partition wall 212 (on the left side in the figure). In other words, the storage area 222 is separated by the partition wall 212 and the covering layer X into a space where the external connection terminals 4 are disposed and which allows connection to the outside, and a sealed space that prevents dust and other foreign matter from entering from the outside. The battery cells 3 and the external connection terminals 4 are connected by a connection portion (circuit board 5) embedded in the covering layer X at least below the partition wall 212. As described above, when the battery cells 3 and the external connection terminals 4 are connected by a lead wire 6 without providing a circuit board 5, the connection portion (lead wire 6) can be embedded in the covering layer X at least below the partition wall 212. Here, "the tip of the partition wall 212 contacts the covering layer X" refers to a state in which the tip surface of the partition wall 212 abuts against the surface of the covering layer X, and a state in which the tip of the partition wall 212 is embedded in the covering layer X as shown in the figure, that is, a state in which the tip of the partition wall 212 is positioned below the surface of the covering layer X. From the perspective of more reliably preventing the intrusion of foreign matter such as dust, it is preferable that the tip of the partition wall 212 be positioned at least 1 mm below the surface of the covering layer X. Furthermore, the potting material that protects the circuit board 5 can also be used as a member for sealing the internal space of the case 2, thereby efficiently preventing the intrusion of foreign matter such as dust.

[0025] The height of the circuit components mounted on the circuit board 5 shown in FIG. 4 may be smaller than the height of the legs 214 shown in FIG. 3. The height of the mounted circuit components is the height from the upper surface of the circuit board 5 to the upper surface of the tallest circuit component, and the height of the legs 214 is the height from the tip surface of the partition wall 212 to the tip surface of the leg 214 as shown in FIG. 3. This allows the circuit components to be accommodated in the gap formed between the tip of the partition wall 212 and the upper surface of the circuit board 5 even when the tip of the leg 214 is in contact with the upper surface of the circuit board 5. Furthermore, this gap allows the spaces separated by the partition wall 212 to communicate with each other. This makes it possible to prevent unevenness in the potting material of the coating layer X in each space during the manufacturing process of the battery pack 1. The manufacturing process of the battery pack 1 will be described later.

[0026] The partition wall 212 may be located anywhere in the internal space of the case 2, as long as it is located between the battery cell 3 and the external connection terminal 4 and its tip is positioned below the surface of the covering layer X. For example, as in the modified example shown in FIG. 5 , the partition wall 212 may not surround the external connection terminal 4, but may be provided in a direction that intersects with the line connecting the battery cell 3 and the external connection terminal 4 when the battery is housed in the case 2. Even when such a partition wall 212 is provided, it is possible to prevent dust and other particles from entering the internal space inside the partition wall 212. Note that the slits 211 are not shown in FIG. 5 .

[0027] In this way, the battery pack 1 has the partition wall 212 disposed between the battery cell 3 and the external connection terminal 4 in the internal space of the case 2, and the tip of the partition wall 212 is in contact with the covering layer X, thereby preventing foreign matter such as dust from entering the space inside the partition wall 212. As a result, it is possible to prevent a decrease in the battery performance of the battery pack 1. Furthermore, there is no need to provide a waterproof sheet as in the prior art, which contributes to cost reduction.

[0028] The manufacturing process of the battery pack 1 will now be briefly described with reference to FIGS. 2 and 4. First, the lower case 22 accommodates the battery cells 3, the circuit board 5 connected to the battery cells 3 via lead wires 6, and the external connection terminals 4 arranged on the circuit board 5. Next, molten resin (potting material) is filled into the accommodation area 222 of the lower case 22. At this time, the circuit board 5, a portion of the lead wires 6 located near the circuit board 5, and the lower portions of the external connection terminals 4 are sunk into the molten resin. Furthermore, before the molten resin hardens, the upper case 21 is fixed to the lower case 22, and the tip of the partition wall 212 is inserted into the molten resin as shown in FIG. 4. At this time, the tip of the leg portion 214 of the partition wall 212 may abut against and press downward against the circuit board 5 to prevent the circuit board 5 from floating up and to position it. Then, as the molten resin hardens, a coating layer X is formed, and the circuit board 5 is embedded in the coating layer X. In this manner, the battery pack 1 can be manufactured. The order of the steps is not particularly limited, and for example, the molten resin may be filled into the containing area 222 of the lower case 22, and then the circuit board 5 may be contained before the molten resin hardens.

[0029] (Second embodiment) Next, the battery pack 1 of the second embodiment will be specifically described with reference to Figures 6 to 8. Note that, here, differences from the battery pack 1 of the first embodiment will be described, and descriptions of the same points as the battery pack 1 of the first embodiment will be omitted.

[0030] 6, upper case 21 has a partition wall 215 extending downward from the upper surface thereof. Partition wall 215 extends from partition wall 212 and is disposed on the outer periphery of upper case 21. More specifically, partition wall 215 is disposed substantially parallel to the inner periphery of upper case 21 from the left and right sides of partition wall 212 as shown in the figure along the inner periphery of upper case 21.

[0031] As shown in FIG. 7 , the lower case 22 has a partition plate 223. The partition plate 223 is formed to surround the periphery of the battery cells 3 (not shown) in a plan view. In the storage area 221, a coating layer Y is formed in a groove formed between the inner peripheral surface of the lower case 22 and the partition plate 223. That is, the coating layer Y is formed in the internal space of the case 2, covering the lower part of the outer periphery of the storage area 221. The material of the coating layer Y is the same as the above-mentioned coating layer X, but it may be a material that hardens over time, such as a thermoplastic resin. The width between the inner peripheral surface of the lower case 22 and the outer peripheral surface of the partition plate 223 in this storage area 221 is larger than the width between the inner peripheral surface of the upper case 21 and the outer peripheral surface of the partition wall 215 shown in FIG. 6 . Similar to the battery pack 1 of the first embodiment, the coating layer X is formed in the storage area 222.

[0032] As shown in FIG. 8 , when the upper case 21 and the lower case 22 are assembled, the partition wall 215 extends from the upper inner surface of the upper case 21 toward the coating layer Y, i.e., from above the internal space of the case 2 toward the coating layer Y. The tip of the partition wall 215 contacts the coating layer Y in the accommodation area 221 and contacts the coating layer X in the accommodation area 222. Here, "the tip of the partition wall 215 contacting the coating layer Y and the coating layer X" refers to a state in which the tip surface of the partition wall 215 abuts against the surfaces of the coating layer Y and the coating layer X, and a state in which the tip of the partition wall 215 is embedded in the coating layer Y and the coating layer X, i.e., a state in which the tip of the partition wall 215 is positioned below the surfaces of the coating layer Y and the coating layer X. Note that in this embodiment, the tip of the partition wall 215 contacts both the coating layer Y and the coating layer X. However, depending on the configuration of the partition wall 212, the tip of the partition wall 215 may contact only the coating layer Y. For example, when the partition wall 212 extends across the entire width of the internal space of the case 2, as in the battery pack 1 of the modified example shown in Fig. 5 of the first embodiment, the partition wall 215 is formed to extend from both ends of the partition wall 212. Therefore, the tip of the partition wall 215 may contact only the covering layer Y.

[0033] In this way, the battery pack 1 of the second embodiment not only has the partition wall 212 but also has the partition wall 215 arranged on the outer periphery of the internal space of the case 2, and the tip of the partition wall 215 is in contact with the coating layer Y and the coating layer X, thereby more reliably preventing foreign matter such as dust from entering the internal space of the battery pack 1.

[0034] The manufacturing method of the battery pack 1 of the second embodiment is basically the same as that of the battery pack 1 of the first embodiment. That is, molten resin that will become the coating layer X and the coating layer Y is filled below the lower case 22, and the upper case 21 and the lower case 22 are fixed together before the molten resin hardens. In the battery pack 1 of the second embodiment, the tip of the partition wall 215 is inserted into the molten resin that will form the coating layer Y and the coating layer X before the molten resin hardens.

[0035] Although the embodiments have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure. [Explanation of symbols]

[0036] 1 battery pack, 2 case, 21 upper case, 211 slit, 212 partition wall, 213 terminal partition plate, 214 legs, 215 partition wall, 22 lower case, 221 storage area, 222 storage area, 223 partition plate, 3 battery cell, 4 external connection terminal, 5 circuit board, 6 lead wire, X coating layer, Y coating layer

Claims

1. A battery pack having a battery cell, an external connection terminal, and a case that houses the battery cell and the external connection terminal, the internal space of the case has a first accommodating area that accommodates the battery cells and a second accommodating area that accommodates the external connection terminals; the case has a first covering layer that covers a lower portion of the second accommodating area, and a first partition wall that extends from an upper portion of an internal space of the case toward the first covering layer and is disposed between the battery cell and the external connection terminal; a tip of the first partition is positioned so as to contact the first coating layer; The external connection terminal is connected to the battery cell via a connection portion embedded in the first coating layer.

2. 2. The battery pack according to claim 1, the connection portion includes a circuit board; The battery pack, wherein the first covering layer is formed of a potting material that covers the circuit board.

3. 3. The battery pack according to claim 1, the case has a slit for connecting the external connection terminal to the outside, The first partition wall is disposed to surround the periphery of the external connection terminal excluding the slit and a lower portion thereof.

4. The battery pack according to any one of claims 1 to 3, The first partition has a leg portion extending downward from a tip thereof.

5. The battery pack according to any one of claims 1 to 4, The case further includes a second covering layer that covers a lower portion of the outer periphery of the first storage area, and a second partition wall that extends from above the internal space of the case toward the second covering layer and is extended from the first partition wall and disposed along the outer periphery of the internal space of the case, The battery pack, wherein the tip of the second partition is positioned so as to contact the second covering layer.

Images