Battery pack

Abstract

This invention provides a battery pack that can cool the battery cells more effectively by efficiently circulating air between them. [Solution] According to one aspect of the present invention, a battery pack is provided comprising a case and a plurality of battery cells housed inside the case, wherein the case has openings that allow air from outside the case to flow into the inside of the case, the plurality of battery cells are arranged with gaps between them, and the openings are provided facing the plurality of gaps.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses an energy storage module having an optimal ratio of volume, weight, and / or material / part requirements for the energy that can be stored in the energy storage module, and being as safe as possible.

[0003] This energy storage module is particularly based on a battery pack for supplying power to a power tool, which consists of a plurality of cells electrically interconnected for energy storage. The cells are proposed to be electrochemical storage cells consisting of dimensionally unstable flexible cell casings. Also, it relates to a power tool including at least one such energy storage module.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the prior art disclosed in Patent Document 1 still has room for improvement.

[0006] In view of the above circumstances, the present invention aims to provide a battery pack that can more effectively cool the battery cells by efficiently flowing air between the battery cells.

Means for Solving the Problems

[0007] According to one aspect of the present invention, a battery pack is provided comprising a case and a plurality of battery cells housed inside the case, wherein the case has openings that allow air from outside the case to flow into the case, the plurality of battery cells are arranged with gaps between them, and the openings are provided opposite to the plurality of gaps.

[0008] In this configuration, the battery cells can be cooled more effectively by efficiently circulating air between them. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view of the object from above. [Figure 2] This is an overall perspective view of the battery pack. [Figure 3] This is an exploded perspective view showing the configuration of the wiring board, battery cell, and sealing member. [Figure 4] This is an exploded perspective view showing the configuration of the case, wiring board, battery cells, and sealing members. [Figure 5] This is an overall view of the battery pack. [Figure 6] This is an overall view of the battery pack. [Figure 7] This is a cross-sectional view illustrating the internal structure of the battery pack, shown in the direction of the arrow A-A in Figure 5. [Figure 8] Figure 5 shows a cross-sectional perspective view illustrating the opening, taken in the direction of the B-B arrow. [Figure 9] Figure 6 shows a cross-sectional perspective view illustrating the opening, taken along the line C-C. [Figure 10] This is a cross-sectional perspective view illustrating the internal structure of the battery pack, with some components of the battery pack omitted and shown in the direction of the DD arrow in Figure 6. [Figure 11] This is an enlarged view illustrating the opening shown in area E of Figure 6. [Figure 12] This is an enlarged view illustrating the opening shown in region F of Figure 7. [Figure 13]It is a cross-sectional view for explaining a modification example of the case, shown in the direction of arrow A-A shown in FIG. 5. [Figure 14] It is an overall perspective view of the battery pack for explaining a modification example of the case. [Figure 15] It is an overall view showing a modification example of the opening.

Mode for Carrying Out the Invention

[0010] Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. Various characteristic matters shown in the following embodiments can be combined with each other.

[0011] <Object 100> First, the object 100 according to an embodiment will be described.

[0012] FIG. 1 is a perspective view of the object seen from above.

[0013] In the following description, based on "up", "down", "left", "right", "front" and "rear" shown in FIG. 1, the directions of the object 100 and each member constituting the object 100 are defined. Further, in the following description, up is also referred to as "upper side" or "above", and down is also referred to as "lower side" or "below". Also, the direction formed by up and down is referred to as "vertical" or "vertical direction". The same applies to "left", "right", "front" and "rear".

[0014] The object 100 shown in FIG. 1 is a portable grass cutter 101. This grass cutter 101 includes a cutting blade 200, a main body 300, an operation lever 400, a handle 500, and a battery pack 1. The grass cutter 101 is a shoulder strap type grass cutter in which an electric motor (not shown) is adopted as a power source. Also, although the object 100 takes the grass cutter 101 as an example, it is not particularly limited as long as it is various electric machines using the battery pack 1. For example, the object 100 may be an electric working machine, an electric tool, an industrial machine, etc. to which the battery pack 1 is detachable. Hereinafter, the case where the object 100 is the grass cutter 101 will be described as an example.

[0015] As shown in FIG. 1, the mower 101 has a disk-shaped-shaped shaped in FIG. 1, the mower 101 has a disk-shaped cutting blade 200 provided on the front side. The cutting blade 200 is configured to rotate by the rotational power of an electric motor (not shown), and is configured to be able to cut grass and the like by rotating. Specifically, a chip saw is adopted for the cutting blade 200.

[0016] The cutting blade 200 is connected to the front side of the operation handle 400. The operation handle 400 is a pipe-shaped member extending in the front-rear direction, and has a drive transmission shaft (not shown) inside. The operation handle 400 is configured to transmit power to the cutting blade 200 by the drive transmission shaft. The operation handle 400 has a main body portion 300 provided on the rear side.

[0017] A handle 500 is attached to the operation handle 400 between the cutting blade 200 and the main body portion 300. The handle 500 is a portion that is gripped and operated by the operator's hand. Further, the main body portion 300 has an electric motor (not shown), a control unit (not shown), etc. inside.

[0018] A battery pack 1 is detachably attached to the rear of the main body portion 300. The battery pack 1 is a battery pack 1 that can be detached by moving it relative to the mower 101 in the left-right direction, which is a predetermined direction.

[0019] <000010​​​​​​Figure 2 is an overall perspective view of the battery pack. Figure 3 is an exploded perspective view showing the configuration of the wiring board, battery cells, and sealing members. Figure 4 is an exploded perspective view showing the configuration of the case, wiring board, battery cells, and sealing members. Figures 5 and 6 are overall views of the battery pack. Figure 7 is a cross-sectional view illustrating the internal configuration of the battery pack, shown in the direction of arrow A-A in Figure 5. Figure 8 is a cross-sectional perspective view illustrating the opening, shown in the direction of arrow B-B in Figure 5. Figure 9 is a cross-sectional perspective view illustrating the opening, shown in the direction of arrow C-C in Figure 6. Figure 10 is a cross-sectional perspective view illustrating the internal configuration of the battery pack, shown in the direction of arrow DD in Figure 6, with some parts of the battery pack omitted. Figure 11 is an enlarged view illustrating the opening, shown in area E in Figure 6. Figure 12 is an enlarged view illustrating the opening, shown in area F in Figure 7. Figure 13 is a cross-sectional view illustrating a modified case, shown in the direction of arrow A-A in Figure 5. Figure 14 is an overall perspective view of the battery pack illustrating a modified case. Figure 15 is an overall view showing a modified example of the opening.

[0021] In the following explanation, the orientation of Battery Pack 1 and each component constituting Battery Pack 1 is defined based on "up," "down," "left," "right," "front," and "rear" as shown in Figures 2 to 15. Furthermore, in the following explanation, "up" will also be referred to as "upper side" or "upward," and "down" will also be referred to as "lower side" or "downward." The direction formed by "up" and "down" will be referred to as "up and down" or "up and down direction." These also apply to "left," "right," "front," and "rear."

[0022] As shown in Figure 2, the battery pack 1 is box-shaped and includes a case 2. The case 2 includes an upper outer housing 21 and a lower outer housing 22, which are divided vertically by planes defined by the front and rear and left and right sides. The upper outer housing 21 and the lower outer housing 22 are fixed together with fastening members such as screws (not shown).

[0023] As shown in Figures 3 and 4, the box formed by the upper outer housing 21 and the lower outer housing 22 houses an inner housing 23, a lever 24, a spring 25, a wiring board 3, a plurality of battery cells 4, and a sealing member 5. In other words, the battery pack 1 comprises a plurality of battery cells 4 housed inside the case 2 and a sealing member 5.

[0024] As shown in Figure 4, the upper external housing 21 is lid-shaped and, when assembled to the lower external housing 22, houses the above-mentioned components in the case 2. The upper external housing 21 also includes a lever mounting portion 21a and a terminal mounting portion 21b.

[0025] The lever mounting portion 21a has a hole formed on the rear side of the upper outer housing 21, into which the lever 24 is inserted from below to above in the case 2. As shown in Figure 5, the terminal mounting portion 21b has a plurality of holes formed on the front side of the upper outer housing 21. Specifically, the terminal mounting portion 21b has six holes. The connection terminals 31c of the wiring board 3 are positioned (inserted) inside the holes of the terminal mounting portion 21b, and when the battery pack 1 is attached to the brush cutter 101, the terminals (not shown) of the brush cutter 101 are connected to the connection terminals 31c of the wiring board 3. The configuration of the lever 24 and the connection terminals 31c of the wiring board 3 will be described in detail later.

[0026] As shown in Figure 4, the lower external housing 22 is box-shaped and configured to accommodate various components inside. The lower external housing 22 also has an opening 22a on the left wall and an opening 22b on the right wall. Specifically, the opening 22a is formed on the left wall by 13 openings arranged in the front-to-back direction. Similarly, the opening 22b is formed on the right wall by 13 openings arranged in the front-to-back direction. Furthermore, the 13 openings in openings 22a and 22b are configured to correspond to each other in the front-to-back and up-to-down directions. In other words, the openings 22a and 22b are arranged to face each other in the left-to-right direction.

[0027] As shown in Figure 4, the internal housing 23 is housed inside the lower external housing 22. The internal housing 23 is box-shaped and configured to house various components inside. The internal housing 23 has an opening 23a on the left wall and an opening 23b on the right wall. Specifically, the opening 23a is formed on the left wall by 13 openings arranged in the front-to-back direction. Similarly, the opening 23b is formed on the right wall by 13 openings arranged in the front-to-back direction. Furthermore, the openings 23a and 23b are configured so that their respective 13 openings correspond to each other in the front-to-back and up-to-down directions. In other words, the openings 23a and 23b are arranged to face each other in the left-to-right direction.

[0028] Furthermore, as shown in Figure 8, the openings 22a and 23a are arranged so that when viewed from the left side with the inner housing 23 attached to the lower outer housing 22, the 13 openings in each opening coincide. The openings 22a and 23a communicate with each other to form the first opening OP1.

[0029] Furthermore, when the inner housing 23 is attached to the lower outer housing 22, the 13 openings in each opening are arranged to coincide when viewed from the right side. The second opening OP2 is formed when the openings 22b and 23b communicate with each other.

[0030] The first opening OP1 and the second opening OP2 are configured to allow air to flow through them. In other words, the case 2, consisting of the lower outer housing 22 and the inner housing 23, has the first opening OP1 and the second opening OP2 as openings OP that allow air from outside the case 2 to flow into the inside of the case 2. That is, the opening OP has the first opening OP1 and the second opening OP2. Specifically, as shown in Figure 9, the air is configured to flow from the first opening OP1 to the second opening OP2.

[0031] As shown in Figure 7, the lower outer housing 22 is provided with a spring mounting portion 22c on its rear upper side, and a spring 25 is configured to be attached to the spring mounting portion 22c. The spring 25 is a spiral spring. The upper side of the spring 25 is inserted into the spring mounting portion 24a of the lever 24. The lever 24 is inserted into the lever mounting portion 21a on its upper side, and is positioned to extend and retract relative to the lever mounting portion 21a (upper outer housing 21) when the upper outer housing 21 and the lower outer housing 22 are assembled. When the lever 24 extends, the battery pack 1 is fixed to the brush cutter 101, and when the lever 24 retracts, the fixed battery pack 1 can be removed from the brush cutter 101.

[0032] Furthermore, as shown in Figure 7, the internal housing 23 contains multiple battery cells 4 and sealing members 5. The battery cells 4 are rechargeable batteries, such as pouch-type (laminated), prismatic, or cylindrical lithium-ion rechargeable batteries. In the following description, the battery cells 4 will be described as pouch-type lithium-ion batteries.

[0033] Furthermore, the number of battery cells 4 and the specifications of each battery cell 4 are set so that the battery pack 1 has a sufficiently high output and charging capacity suitable for work with the brush cutter 101. Specifically, 14 battery cells 4 of the same specifications are connected in series so that the battery pack 1 has a predetermined output and charging capacity.

[0034] As shown in Figure 3, each battery cell 4 is positioned in a predetermined location by being inserted into the gap 5a provided by the sealing member 5. As shown in Figure 12, the multiple battery cells 4 positioned in the predetermined location are arranged with gaps GA between them. In this case, the battery cells 4 are arranged in the front-to-back direction, that is, in the insertion / removal direction. In other words, the multiple gaps GA are arranged in the front-to-back direction (an example of the first direction D1). Specifically, 13 gaps GA are formed in the front-to-back direction by 14 battery cells 4. The width (length in the front-to-back direction) of the gaps GA in this case is 2 mm. The width of the gaps GA is often, for example, 0.5 to 5 mm, preferably 1 to 3 mm, and more preferably 1.5 to 2.5 mm. Specifically, for example, the width of the gap GA is 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5 mm, and may also be within the range of any two of the values ​​exemplified here.

[0035] Furthermore, as shown in Figure 11, the opening OP is provided facing multiple gaps GA. Specifically, on the left side of the battery pack 1, the first opening OP1 is positioned facing a gap GA, and the gap GA is exposed from the first opening OP1. On the right side of the battery pack 1, the second opening OP2 is positioned facing a gap GA, and the gap GA is exposed from the second opening OP2. In other words, in the battery pack 1, at least one of the multiple gaps GA is exposed from the opening OP. With this configuration, it becomes possible to efficiently circulate air between the battery cells 4, and the battery cells 4 can be cooled more effectively.

[0036] Furthermore, the openings OP are preferably configured to correspond to the number and location of the gaps GA, and are preferably provided at a position opposite each of the multiple gaps GA. In other words, the openings OP are preferably provided as a first opening OP1 on the left side of the battery pack 1 and a second opening OP2 on the right side of the battery pack 1, so as to correspond to the number and location of the multiple gaps GA. Specifically, in the battery pack 1, all openings OP are preferably provided at positions opposite the multiple gaps GA, and the gaps GA are preferably exposed from the openings OP. In other words, all of the multiple gaps GA are preferably exposed from the first opening OP1 on the left side of the battery pack 1 and from the second opening OP2 on the right side of the battery pack 1. With this configuration, it becomes possible to circulate air through all the gaps GA, and all the battery cells 4 can be cooled.

[0037] Furthermore, as shown in Figure 9, specifically, the opening OP may consist of a first opening OP1 having 13 openings on the left side of the battery pack 1, corresponding to the 13 gaps GA, and a second opening OP2 having 13 openings on the right side of the battery pack 1. In other words, the opening OP may include multiple openings, with each opening positioned opposite one gap GA. In other words, it may be configured so that one gap GA is exposed through one opening. This configuration allows for cooling of the battery cells 4 while preventing foreign matter larger than the area of ​​each opening from entering the case 2. Moreover, the openings OP and gaps GA may be arranged in a substantially linear fashion in the left-right direction. That is, air flowing into the case 2 from the first opening OP1 flows substantially linearly through the gaps GA and the second opening OP2, and then flows out through the second opening OP2.

[0038] Furthermore, as shown in Figure 6, the opening OP is composed of multiple openings arranged in the front-to-back direction, and the opening area of ​​the openings increases as it approaches the center in the front-to-back direction. In other words, the opening OP has the largest area at the center of the case 2 in the front-to-back direction. As a result, the opening area of ​​the opening OP located opposite the multiple gaps GA increases as it approaches the center in the front-to-back direction (an example of the first direction D1). In other words, the exposed area of ​​the multiple gaps GA from the opening OP increases as it approaches the center in the front-to-back direction. With this configuration, it becomes possible to circulate more air in the center of the battery pack 1. As a result, it becomes possible to actively cool the center of the battery pack 1 where heat tends to accumulate, and the battery pack 1 can be cooled more uniformly.

[0039] Furthermore, as shown in Figure 3, each battery cell 4 is equipped with a positive electrode 4c and a negative electrode 4c. Multiple battery cells 4 are arranged in a predetermined direction with their electrodes 4c on the same side. Specifically, multiple battery cells 4 are arranged in the front-to-back direction, i.e., the direction in which the battery pack 1 is inserted and removed, with their electrodes 4c facing upwards. In addition, multiple battery cells 4 are arranged such that the arrangement of the positive electrode 4c and the negative electrode 4c alternates between the right and left sides, that is, the front and back sides of adjacent battery cells 4 are reversed.

[0040] Each battery cell 4 is inserted into a gap 5a provided in the sealing member 5. The sealing member 5 has the same number of gaps 5a as the number of battery cells 4. Specifically, the sealing member 5 has 14 gaps 5a, and one battery cell 4 is inserted into each gap 5a. Furthermore, as shown in Figures 7 and 10, when each battery cell 4 is inserted into a gap 5a of the sealing member 5, the gap 5a and the battery cell 4 are in close contact. Specifically, the battery cell 4 is inserted into the gap 5a of the sealing member 5 with the pouch portion protruding outward from the side of the battery cell 4 folded. This causes the gap 5a and the battery cell 4 to be in close contact. In addition, when the sealing member 5 is housed inside the internal housing 23, the sealing member 5 and the internal housing 23 are in close contact. As a result, the internal housing 23, the multiple battery cells 4 and the sealing member 5 form a first space IS1 above the sealing member 5 and a second space IS2 below the sealing member 5. In other words, the sealing member 5 is configured to divide the inside of the case 2 into a first space IS1 and a second space IS2.

[0041] As shown in Figure 7, the first space IS1 and the second space IS2 are configured not to communicate with each other by the sealing member 5 being in close contact with the internal housing 23 and the battery cell 4. In other words, the second space IS2 is configured not to communicate with the first space IS1. That is, the second space IS2 has sealing properties such that it does not communicate with the first space IS1 by the sealing member 5 being in close contact with at least the battery cell 4. With this configuration, the sealing member 5 can protect the components located in the second space IS2 from water, dirt, etc. that enter through the first space IS1. Furthermore, with this configuration, when the brush cutter 101 shown in Figure 1 is being used to cut grass etc. growing from the ground with the cutting blade 200 while the battery pack 1 is attached, it is possible to suppress water that has entered the first space IS1 from outside the case 2 and entered the second space IS2. That is, it is possible to suppress water from coming into contact with the electrodes 4c of the battery cell 4 located in the second space IS2.

[0042] Furthermore, as shown in Figure 13, a lever storage space R is preferably formed in the case 2. The lever storage space R is a space formed when the upper outer housing 21 and the lower outer housing 22 are assembled. The lever 24 is movably positioned in the lever storage space R relative to the upper outer housing 21. In addition, the lever storage space R is configured so as not to communicate with the first space IS1 and the second space IS2 by partitioning the inside of the case 2. In other words, the lever mounting portion 21a is configured not to communicate with the first space IS1 and the second space IS2.

[0043] Furthermore, as shown in Figure 14, the upper outer housing 21 may be provided with a packing P around the terminal mounting portion 21b. This ensures that when the battery pack 1 is attached to the brush cutter 101, the packing P is in close contact with the brush cutter 101 and the upper outer housing 21, preventing communication between the second space IS2 and the outside of the battery pack 1. The packing P can be any material that provides a sealing effect by being in close contact with the brush cutter 101 and the upper outer housing 21; for example, a rubber packing may be used. With this configuration, when the battery pack 1 is attached to the brush cutter 101, the second space IS2 can be isolated from the outside of the case.

[0044] Furthermore, as shown in Figure 8, in the first space IS1, the battery cells 4 housed in the case 2 are positioned between the first opening OP1 and the second opening OP2. In other words, the second opening OP2 is positioned on the opposite side of the first opening OP1 via multiple battery cells 4 and is configured to allow air that has flowed into the case 2 to flow out. This configuration makes it possible to flow air linearly between the battery cells 4, further facilitating the cooling of the battery cells 4. The openings OP are preferably configured to open in the vertical direction when the battery pack 1 is attached to the brush cutter 101. Specifically, when the battery pack 1 is attached to the brush cutter 101, for example, the first opening OP1 is positioned on the ground side and the second opening OP2 is positioned on the overhead side. This configuration allows the airflow from the ground side to the overhead side (upward airflow) to release the heat generated by the heat generated by the battery cells 4 to the overhead side, thereby further cooling the battery cells 4.

[0045] Furthermore, as shown in Figure 8, the sealing member 5 divides the first space IS1 and the second space IS2, so that the battery cell 4 has a first region 4a and a second region 4b, which are defined according to the position where the sealing member 5 is attached. In other words, each battery cell 4 has a first region 4a located in the first space IS1 and a second region 4b located in the second space IS2. Specifically, as shown in Figure 8, the sealing member 5 is attached to the upper side of the battery cell 4. The battery cell 4 also has a first region 4a below the position where the sealing member 5 is attached, and a second region 4b above the position where the sealing member 5 is attached. The second region 4b also includes an electrode 4c located on the upper side of the battery cell 4. In other words, the second region 4b includes the electrode 4c. With this configuration, the electrode 4c in the second region 4b of the battery cell 4 can be protected from the intrusion of water, dirt, etc., thereby preventing malfunctions and damage, while also allowing the first region 4a of the battery cell 4 to be cooled.

[0046] Furthermore, as shown in Figures 7 and 12, a gap GA is formed in the first space IS1. And, as shown in Figure 8, the first space IS1 is configured to communicate with the openings OP, namely the first opening OP1 and the second opening OP2. With this configuration, it is possible to provide a first space IS1 that allows outside air to circulate and a second space IS2 that can prevent the intrusion of water, dirt, etc. As a result, it is possible to cool the battery cell 4 located in the first space IS1 while protecting the components located in the second space IS2.

[0047] As shown in Figure 7, the volume of the first space IS1 is preferably larger than the volume of the second space IS2. That is, the first region 4a is preferably set up so that most of the battery cell 4, excluding the electrodes 4c of the battery cell 4, is located in the first space IS1. Specifically, the volume of the first space IS1 is approximately three times the volume of the second space IS2. The volume of the first space IS1 is preferably larger than the volume of the second space IS2 by an arbitrary ratio, and this arbitrary ratio is, for example, preferably 1.4 to 10, preferably 2 to 7, and more preferably 3 to 5. Specifically, for example, any ratio can be 1.4, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.4, 3.6, 3.8, 4, 4.2, 4.4, 4.6, 4.8, 5, 5.2, 5.4, 5.6, 5.8, 6, 6.2, 6.4, 6.6, 6.8, 7, 7.2, 7.4, 7.6, 7.8, 8, 8.2, 8.4, 8.6, 8.8, 9, 9.2, 9.4, 9.6, 9.8, 10, and may also be within the range of any two of the values ​​exemplified here. According to this embodiment, by protecting the electrodes 4c of the battery cell 4 from the ingress of water, dust, etc., malfunctions and damage can be prevented while cooling most of the battery cell 4.

[0048] As shown in Figure 3, a wiring board 3 is positioned above the battery cell 4, electrically connected to the electrodes 4c. In other words, the wiring board 3 is electrically connected to the electrodes 4c of the battery cell 4. Specifically, the wiring board 3 has a first wiring board 31 and a second wiring board 32. The first wiring board 31 and the second wiring board 32 are electrically connected by a connector connection portion 31b on the first wiring board 31 and a connector 32b on the second wiring board 32. The second wiring board 32 has an electrode mounting portion 32c, into which the electrodes 4c are inserted and fixed by welding. Alternatively, the electrodes 4c may be fixed by press-fitting them into the electrode mounting portion 32c. In this case, it is easy to replace a defective battery cell 4 with a new one. Furthermore, a bolt 33 is inserted into the through hole 31a of the first wiring board 31, and the threaded portion of the bolt 33 protruding from the first wiring board 31 is screwed into the threaded hole 32a of the second wiring board 32. This fixes the first wiring board 31 and the second wiring board 32 together.

[0049] Furthermore, the first wiring board 31 is provided with a connection terminal 31c on its front upper side. As shown in Figure 5, the connection terminal 31c is configured to be electrically connectable via the terminal mounting portion 21b of the upper outer housing 21 when the first wiring board 31 is housed in the case 2. This allows the battery pack 1 and the brush cutter 101 to be electrically connected when the battery pack 1 is attached to the brush cutter 101.

[0050] Furthermore, the sealing member 5 is preferably an elastic material. The elastic material can be made of at least one material selected from the group consisting of norbornene rubber (NB), chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR), urethane rubber, fluororubber, and silicone rubber. With this embodiment, the sealing performance can be further improved by the elastic force of the sealing member 5. Note that the sealing member 5 is not limited to an elastic material, but may be any material that can tightly seal the battery cell 4 and the internal housing 23, for example, a material that tightly seals by plastic deformation, a packing, a sealant, etc.

[0051] Furthermore, the sealing member 5 may be composed of a single component. This configuration allows for improved airtightness and also prevents an increase in the number of components in the battery pack 1.

[0052] [others] The battery pack 1 according to one embodiment may be implemented in the following manner.

[0053] The opening OP shown in Figure 6 was described as a case where there are multiple openings arranged in the front-to-back direction, but it is not limited to this. As shown in Figure 15, for example, the opening OP can also be made up of a single opening. That is, the first opening OP1 and the second opening OP2 can each be made up of a single opening. With this configuration, more air can be circulated into the gap GA, and as a result, the battery cell 4 can be cooled more effectively.

[0054] Furthermore, they may be provided in the following embodiments.

[0055] (1) A battery pack comprising a case and a plurality of battery cells housed inside the case, wherein the case has an opening that allows air from outside the case to flow into the case, the plurality of battery cells are arranged with gaps between them, and the opening is provided opposite to the plurality of gaps.

[0056] This configuration allows for efficient airflow between battery cells, thereby enabling better cooling of the battery cells.

[0057] (2) A battery pack as described in (1) above, wherein the opening is provided at a position opposite each of the plurality of gaps.

[0058] In this configuration, air can be circulated through all gaps, allowing all battery cells to be cooled.

[0059] (3) A battery pack according to (1) or (2) above, wherein the opening has a first opening and a second opening, the first opening is configured to allow air to flow into the interior of the case, and the second opening is located on the opposite side of the first opening via the plurality of battery cells and is configured to allow the air that has flowed into the interior of the case to flow out.

[0060] This configuration allows for a linear flow of air between the battery cells, making it easier to cool the battery cells.

[0061] (4) A battery pack according to (1) to (3) above, further comprising a sealing member, wherein the sealing member is configured to divide the inside of the case into a first space and a second space, the first space is configured to communicate with the opening, and the second space is configured not to communicate with the first space.

[0062] In this configuration, a first space that allows external air to circulate and a second space that prevents the intrusion of water, dust, etc. can be provided. As a result, the battery cells located in the first space can be cooled while the components located in the second space can be protected.

[0063] (5) A battery pack as described in (4) above, wherein each battery cell has a first region located in the first space and a second region located in the second space, and the second region includes electrodes.

[0064] In this embodiment, the electrodes in the second region of the battery cell can be protected from the ingress of water, dust, etc., thereby preventing malfunctions and damage, while simultaneously cooling the first region of the battery cell.

[0065] (6) A battery pack as described in (4) or (5) above, wherein the volume of the first space is greater than the volume of the second space.

[0066] In this configuration, the electrodes of the battery cell can be protected from the ingress of water, dust, etc., thereby preventing malfunctions and damage, while also allowing the majority of the battery cell to be cooled.

[0067] (7) A battery pack according to any one of (1) to (6) above, wherein the plurality of gaps are arranged in a line in a first direction, and the opening area of ​​the opening provided at a position opposite the plurality of gaps increases toward the center in the first direction.

[0068] This configuration allows for greater airflow in the center of the battery pack. As a result, the center of the battery pack, where heat tends to accumulate, can be actively cooled, enabling more uniform cooling of the battery pack.

[0069] (8) A battery pack according to any one of (1) to (7) above, wherein the opening includes a plurality of openings, and one of the openings is provided in a position opposite one of the gaps.

[0070] This configuration allows for cooling of the battery cells while preventing foreign objects larger than the area of ​​each opening from entering the case. Of course, this is not always the case.

[0071] Finally, various embodiments of the present invention have been described, but these are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of Symbols]

[0072] 100: Object 101: Brush cutter 200: Cutting blade 300: Main body 400: Operating rod 500: Handle 1: Battery pack 2: Case 21: Upper external housing 21a: Lever mounting part 21b: Terminal mounting section 22: Lower external housing 22a: Opening 22b: Opening 22c: Spring mounting part 23: Internal Housing 23a: Opening 23b: Opening 24: Lever 24a: Spring mounting section 25: Spring 3: Wiring board 31: First wiring board 31a: Through hole 31b: Connector connection part 31c: Connection terminal 32: Second wiring board 32a: Screw hole 32b: Connector 32c: Electrode mounting section 33: Bolt 4: Battery cell 4a: First area 4b: Second area 4c: Electrode 5: Sealing member 5a: Gap D1: First direction GA: Gap IS1: First space IS2: The Second Space OP: Opening OP1: First opening OP2: Second opening P: Packing R: Lever storage space

Claims

1. It is a battery pack, The device comprises a case and a plurality of battery cells housed inside the case, The case has an opening that allows air from outside the case to flow into the inside of the case. The aforementioned plurality of battery cells are arranged with gaps between them, The aforementioned opening is a battery pack provided opposite the plurality of gaps.

2. In the battery pack according to claim 1, The aforementioned openings are provided in a battery pack located opposite each of the aforementioned plurality of gaps.

3. In the battery pack according to claim 1, The opening has a first opening and a second opening, The first opening is configured to allow air to flow into the inside of the case. A battery pack in which the second opening is located on the opposite side of the first opening via the plurality of battery cells and is configured to allow the air that has flowed into the interior of the case to flow out.

4. In the battery pack according to claim 1, Further comprising a sealing member, The sealing member is configured to divide the inside of the case into a first space and a second space. The first space is configured to communicate with the opening, A battery pack in which the second space is configured not to communicate with the first space.

5. In the battery pack according to claim 4, Each of the battery cells has a first region located in the first space and a second region located in the second space. The second region is a battery pack including electrodes.

6. In the battery pack according to claim 4, A battery pack in which the volume of the first space is greater than the volume of the second space.

7. In the battery pack according to claim 1, The aforementioned multiple gaps are arranged in a line in the first direction, A battery pack in which the opening area of ​​the openings provided at positions opposite the plurality of gaps increases as it approaches the center in the first direction.

8. In the battery pack according to claim 1, The aforementioned opening includes a plurality of openings, A battery pack in which one of the openings is located opposite one of the gaps.

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