Battery packs and power tools

Abstract

A battery pack includes: a battery; a first circuit substrate; an outer case; and an inner case disposed inside the outer case. The battery and the first circuit substrate are accommodated in the inner case. A sensor portion for detecting water ingress is provided between the outer case and the inner case.

Description

Technical Field

[0001] The invention relates to a battery pack and an electric tool. Background Art

[0002] Liquids such as water that infiltrate the battery pack can cause migration or short circuits. Therefore, battery packs with countermeasures against water intrusion have been proposed. For example, Patent Document 1 below describes a technology that prevents water intrusion by adopting a double internal structure. Furthermore, Patent Document 2 below describes a technology that improves battery safety by detecting liquid intrusion into the battery housing.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-50093

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 11-191403. Summary of the Invention

[0007] Problems to be solved by the invention

[0008] However, the technology described in Patent Document 1 uses a dual structure to protect the connector, which is insufficient as a technology for protecting the battery cell from water ingress. Furthermore, the technology described in Patent Document 2 detects water ingress while the battery cell is submerged, making it insufficient as a technology for achieving battery safety.

[0009] Therefore, one object of the present invention is to provide a battery pack and an electric power tool with further improved safety against submersion in water.

[0010] Solutions to Problems

[0011] In order to solve the above problems, the present invention is:

[0012] A battery pack includes: a battery; a first circuit substrate; an outer shell; and an inner shell disposed inside the outer shell.

[0013] The battery and the first circuit substrate are housed in the inner housing.

[0014] A sensor portion for detecting water intrusion is provided between the outer case and the inner case.

[0015] Furthermore, the present invention is an electric tool including the above-mentioned battery pack.

[0016] Effects of the Invention

[0017] According to at least one embodiment of the present invention, the safety of the battery pack against water immersion can be further improved. It should be noted that the content of the present invention should not be interpreted as being limited to the effects exemplified in this specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a diagram showing an example of the appearance of a battery pack according to one embodiment.

[0019] Figure 2 These are diagrams referred to when describing an example of the internal structure of a battery pack according to one embodiment.

[0020] Figure 3 These are diagrams referred to when describing an example of the internal structure of a battery pack according to one embodiment.

[0021] Figure 4 These are diagrams referred to when describing an example of the internal structure of a battery pack according to one embodiment.

[0022] Figure 5 These are diagrams referred to when describing an example of the internal structure of a battery pack according to one embodiment.

[0023] Figure 6 A and Figure 6 B is a diagram referred to when explaining an example of arrangement of submergence detection sensors according to one embodiment.

[0024] Figure 7 A and Figure 7 B is a diagram referred to when explaining an example of the electrical configuration of a battery pack according to one embodiment.

[0025] Figure 8 This is a diagram showing a configuration example of a water submergence detection sensor according to one embodiment.

[0026] Figure 9 These are diagrams referred to when describing an example of the electrical configuration of a battery pack according to one embodiment.

[0027] Figure 10 This is a flowchart to be referred to when describing a first operation example of the battery pack according to one embodiment.

[0028] Figure 11 This is a flowchart to be referred to when describing a second operation example of the battery pack according to one embodiment.

[0029] Figure 12 It is a diagram for explaining an application example. DETAILED DESCRIPTION

[0030] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0031] <One embodiment>

[0032] Modifications

[0033] Application Examples

[0034] The embodiments and the like described below are preferred specific examples of the present invention, and the contents of the present invention are not limited to these embodiments and the like.

[0035] <One embodiment>

[0036] [summary]

[0037] First, an overview of the present embodiment will be described. The battery pack involved in the present embodiment has a dual structure having an outer shell (also referred to as an outer shell, etc.) and an inner shell (also referred to as an inner shell, etc.) housed in the outer shell. The battery cells are housed in the inner shell. When water intrusion into the battery pack is detected by a water intrusion detection sensor disposed between the outer shell and the inner shell, the output of the battery pack is cut off by a control system in the inner shell that is not submerged in water. In this way, the migration of the battery cells themselves and the short circuit of the battery cells are protected. Below, one embodiment is described in detail.

[0038] [Battery Pack]

[0039] (Example of battery pack appearance)

[0040] Figure 1 : This is a diagram showing an example of the appearance of the battery pack (battery pack 1) involved in this embodiment. The battery pack 1 is formed of a resin or the like, and has an outer shell 2 that is box-shaped as a whole. The outer shell 2 has an outer upper shell 2a and an outer lower shell 2b. The positive output terminal 3a and the negative output terminal 3b are respectively derived from the upper surface of the outer upper shell 2a. In addition, an operating unit 5 and a display unit 6 indicating the status of the battery are provided on the outer upper shell 2a. The operating unit 5 is a structure that can be operated from the outside, and includes, for example, a power switch described later. The display unit 6 has, for example, a plurality of LEDs (Light Emitting Diodes). For example, when the power switch is pressed, a predetermined number of LEDs are lit according to the remaining capacity of the battery pack 1 (an example of the battery status). Of course, the contents of the operating unit 5 and the display unit 6 are not limited to the above examples.

[0041] (Example of the internal structure of a battery pack)

[0042] Next, refer to Figures 2 to 5 An example of the internal structure of the battery pack 1 will be described. Figure 2 This is an exploded perspective view of the internal structure of the battery pack 1. Figure 3as well as Figure 4 This is an exploded perspective view of the internal structure of a portion of the battery pack 1. Figure 5 This is a cross-sectional view of the internal structure of the battery pack 1 as viewed from one side.

[0043] As described above, the outer case 2 includes an outer upper case 2a and an outer lower case 2b. The outer upper case 2a has a circular hole 21a for inserting the positive output terminal 3a and a circular hole 21b for inserting the negative output terminal 3b. Furthermore, the outer upper case 2a has a hole 22 for inserting the LED lens (described later) and a hole 23 for inserting the power switch.

[0044] The outer upper case 2a and the outer lower case 2b are integrated using, for example, four setscrews 24. For example, by tightening the setscrews 24 near the corners of the outer upper case 2a and the outer lower case 2b, the outer upper case 2a and the outer lower case 2b are integrated. A frame-shaped O-ring 25 made of an elastic member is interposed between the outer upper case 2a and the outer lower case 2b. This seals the interior of the outer case 2, enhancing its waterproofing.

[0045] An inner shell 30 made of resin or the like is arranged and housed in the outer shell 2. The inner shell 30 includes an inner upper shell 31 and an inner lower shell 32. The inner upper shell 31 and the inner lower shell 32 are integrated, for example, by engaging a claw-shaped protrusion provided on the inner upper shell 31 with a recessed portion of the inner lower shell 32 (illustration of these structures is omitted). The fastening screw 33 integrates the upper battery holder and the lower battery holder described later. An O-ring 34 made of an elastic component and in the shape of a frame is sandwiched between the inner upper shell 31 and the inner lower shell 32. As a result, the inner shell 30 of the battery pack 1 is sealed, and the waterproofness of the inner shell 30 can be improved. Here, the O-ring is a component formed of an annular elastic resin. As described above, the outer shell 2 and the inner shell 30 each independently form a sealed structure. In addition, the inner upper shell 31 has a recessed portion 31a that is recessed from the top to the bottom. The recessed portion 31 a is located in the space between the outer case 2 and the inner case 30 .

[0046] The battery assembly 40 is housed in the inner housing 30. Figure 3As shown, the battery assembly 40 has a battery 401, a battery holder 402, a contact 403, a contact 404 and a first circuit substrate 405. The battery 401 has one or more cylindrical battery cells. In this embodiment, the battery 401 has 16 battery cells. Of course, the number of battery cells and the connection method can be changed appropriately. The battery holder 402 is a holder that stores and holds each battery cell. The battery holder 402 involved in this embodiment has an upper battery holder 402a and a lower battery holder 402b, and the two are integrated by fastening screws 33, thereby storing and holding the battery 401 through the battery holder 402. Contacts 403 and 404 are metal plates welded to the positive or negative terminals of the battery 401. An IC (Integrated Circuit) and the like that perform controls for ensuring the safety of the battery 401 are installed on the first circuit substrate 405. The output of the battery 401 is transmitted via the output line 61 (refer to Figure 2 as well as Figure 5 ) is supplied to the positive output terminal 3a and is supplied to the negative output terminal 3b via the output line 62.

[0047] like Figure 4 As shown, the operating unit 5 includes a power switch 501. The power switch 501 is inserted into the hole 23. Furthermore, the display unit 6 includes an LED lens 601; a lens waterproof rubber 602; an LED substrate 603 (an example of a second circuit substrate) as an example of a circuit substrate; an LED substrate holder 604; LED substrate fastening screws 605; a flexible substrate 606 as an FPC (Flexible Printed Circuit); and an LED element (not shown) mounted on the LED substrate 603.

[0048] The LED lens 601 is inserted into the hole 22 of the outer upper housing 2a. Light from the LED element mounted on the LED substrate 603 is guided to the upper surface of the outer upper housing 2a via the LED lens 601. A lens waterproof rubber 602 is positioned around the LED lens 601 and the power switch 501 to prevent water from entering the LED substrate holder 604. The LED substrate 603 is a substrate on which an IC, etc., that controls the light emission of the LED element and the LED lens 601 is mounted. Furthermore, the LED substrate 603 is provided with terminals that connect when the power switch 501 is pressed. When the power switch 501 is pressed, electrical conduction occurs, causing the LED element to emit light. The LED substrate holder 604 has a box-like shape and holds the LED substrate 603 on its bottom surface. For example, four LED substrate fastening screws 605 are tightened near the corners of the LED substrate 603 and the LED substrate holder 604 to secure the LED substrate 603 to the LED substrate holder 604. One end of the flexible substrate 606 is connected to the LED substrate 603. The flexible substrate 606 is drawn out from the bottom surface of the LED substrate holder 604, and the other end thereof is connected to the first circuit substrate 405. Figure 5 As shown, a space defined by the LED substrate holder 604 is formed in the space between the outer housing 2 and the inner housing 30 .

[0049] It should be noted that the battery pack 1 includes one or more water submersion detection sensors as a sensor unit. These sensors are located in the space between the outer case 2 and the inner case 30. In this embodiment, two water submersion detection sensors (water submersion detection sensors 80a and 80b) are located in the space between the outer case 2 and the inner case 30. To ensure that the water submersion detection sensors effectively and accurately detect water intrusion into the battery pack 1, it is effective to locate the water submersion detection sensors in a location in the space between the outer case 2 and the inner case 30 where moisture is likely to accumulate.

[0050] Figure 6 A is a diagram showing a specific example of the configuration position of the submergence detection sensor 80a. Figure 6 A and Figure 6 In B, the diagram of a part of the structure is simplified. Figure 6As shown in Figure A, when the power switch 501 is pressed, a small gap forms between the power switch 501 and the outer upper housing 2a. Moisture can enter through this gap. Any intruding moisture accumulates within the LED substrate holder 604. Therefore, a water submersion detection sensor 80a is positioned near the operating unit 5 and display unit 6. Specifically, the water submersion detection sensor 80a is positioned on the LED substrate 603 that connects the power switch 501 and the LED elements. This arrangement efficiently detects water intrusion into the space between the outer housing 2 and the inner housing 30.

[0051] Furthermore, in this embodiment, a recess 31a is formed on the upper surface of the inner upper case 31. This recess 31a allows moisture that enters through the outer case 2 to be stored near the bottom of the recess 31a. In other words, the recess 31a can function as a reservoir for storing moisture. By providing the water intrusion detection sensor 80b in the recess 31a, specifically near the bottom of the recess 31a, it is possible to efficiently detect water intrusion into the space between the outer case 2 and the inner case 30.

[0052] Of course, the water detection sensor can be placed in either or both locations. Furthermore, the water detection sensor can be placed in other locations. For example, the water detection sensor can be placed on a flexible substrate 606 that is routed from within the LED substrate holder 604 and placed in the space between the outer housing 2 and the inner housing 30.

[0053] (Example of the electrical structure of a battery pack)

[0054] Figure 7 A is a diagram showing an example of the electrical structure of a typical battery pack. In a typical battery pack, batteries and a control circuit are arranged in a single-layer casing, and positive and negative output terminals are extended from the casing.

[0055] Figure 7 B is a diagram illustrating an example of the electrical configuration of the battery pack 1. In the battery pack 1 according to this embodiment, a positive output terminal 3a and a negative output terminal 3b extend from the outer case 2. Water submersion detection sensors are provided between the outer case 2 and the inner case 30. For example, water submersion detection sensors 80a and 80b are provided between the outer case 2 and the inner case 30. Figure 8 This diagram shows an example of a submergence detection sensor 80a (which may also be a submergence detection sensor 80b). The submergence detection sensor 80a has a structure in which two comb-shaped wiring patterns 81a and 81b face each other. The distance between adjacent wiring patterns is preferably about 0.5 mm.

[0056] Furthermore, a submersion detection unit 85 and a control circuit unit 90 electrically connected to the submersion detection sensors 80a and 80b are provided in the inner housing 30. The submersion detection unit 85 and the control circuit unit 90 are mounted on the first circuit board 405.

[0057] Figure 9 This figure shows a detailed example of the electrical configuration of the battery pack 1. Water detection sensors 80a and 80b are electrically connected to a water detection unit 85. The water detection unit 85 includes an FET (Field Effect Transistor) 85a connected between a predetermined voltage VDD and ground; a resistor 85b connected between the gate of the FET 85a and the water detection sensors 80a and 80b; and a resistor 85c connected between the FET 85a and ground. The control circuit unit 90 includes a charge and discharge control unit 91a that controls the charging and discharging of the battery 401; and a charge and discharge switch 91b (e.g., two FETs) whose on / off is controlled by the charge and discharge control unit 91a. The charge and discharge control unit 91a is connected between the FET 85a and the resistor 85c in the water detection unit 85. It should be noted that the charge and discharge switch 91b may be connected to the power line on the negative side of the battery 401, rather than the positive side. Alternatively, the water submergence detection unit 85 and the control circuit unit 90 may be provided for each water submergence detection sensor.

[0058] Furthermore, an SCP (Self Control Protector) 95, an example of a fuse with a heater, is connected in series with the charge / discharge switch 91b to the power line on the positive electrode side of the battery 401. The SCP 95 can be blown at any time by the charge / discharge control unit 91a.

[0059] (Battery pack operation example)

[0060] [Basic action example]

[0061] Next, an example of the operation of the battery pack 1 will be described. In the battery pack 1, when at least one of the water submersion detection sensors 80a and 80b detects water submersion between the outer case 2 and the inner case 30, control is performed to shut off the output of the battery pack 1.

[0062] A basic operation example will be described in detail. When there is no water immersion, for example, the wiring patterns 81a and 81b are electrically disconnected, and a high (Hi) signal is supplied to the gate of FET 85a. However, when there is water immersion, the water immersion detection sensor 80a (or alternatively, the water immersion detection sensor 80b) turns on, supplying a low (Lo) signal to the gate of FET 85a, turning on FET 85a. Turning on FET 85a switches the input level to the charge and discharge control unit 91a. This switching transmits the presence of water immersion from the water immersion detection unit 85 to the control circuit unit 90. The charge and discharge control unit 91a detects the presence of water immersion by detecting the switching in the input level. Furthermore, the charge and discharge control unit 91a shuts off the output of the battery pack 1 by opening the charge and discharge switch 91b. Because the charge and discharge control unit 91a is located within the inner housing 30, it can operate even if the waterproofing mechanism of the outer housing 2 fails and water is present between the outer housing 2 and the inner housing 30, thus reliably shutting off the output of the battery pack 1.

[0063] "First Action Example"

[0064] Next, refer to Figure 10 The flowchart below illustrates a first example of the operation of the battery pack 1. The first example of the operation is to shut off the output of the battery pack 1 when water is detected between the outer case 2 and the inner case 30 of the battery pack 1. Furthermore, the output of the battery pack 1 is restored when the water is removed from between the outer case 2 and the inner case 30 (water immersion is resolved).

[0065] When control starts, in step ST11, the charge and discharge control unit 91a turns on the discharge switch of the charge and discharge switch 91b and turns off the charge switch, thereby performing normal output control of the power of the battery pack 1. The process then proceeds to step ST12.

[0066] In step ST12, the sensing data from the water submersion detection sensors 80a and 80b is supplied to the charge / discharge control unit 91a via the water submersion detection unit 85. The charge / discharge control unit 91a then determines whether water is present between the outer housing 2 and the inner housing 30. If the charge / discharge control unit 91a determines that water is not present, the process returns to step ST11 and normal output control continues. If the charge / discharge control unit 91a determines that water is present, the process proceeds to step ST13.

[0067] In step ST13, the charge and discharge control unit 91a performs output cutoff control to turn off the charge and discharge switch 91b. This control cuts off the output of the battery pack 1. The process then proceeds to step ST14.

[0068] In step ST14, after the charge / discharge control unit 91a determines that water has entered the space between the outer housing 2 and the inner housing 30, it then re-determines whether water has entered the space between the outer housing 2 and the inner housing 30 after a predetermined time has passed. If, during this determination process, the charge / discharge control unit 91a again determines that water has entered the space between the outer housing 2 and the inner housing 30, the process returns to step ST13 to continue output cutoff control. If, during the determination process in step ST14, the charge / discharge control unit 91a determines that water has not entered the space, the process returns to step ST11.

[0069] In step ST11 , the charge / discharge control unit 91 a controls the discharge switch of the charge / discharge switch 91 b to turn on, thereby restoring the output of the battery pack 1 that was once shut off, and supplying the power of the battery pack 1 to the load.

[0070] Second Action Example

[0071] Next, refer to Figure 11 The flowchart of FIG. 1 will now describe a second operation example of the battery pack 1. Note that the operations from step ST11 to step ST13 are the same as those in the first operation example, and therefore, duplicate descriptions will be omitted as appropriate.

[0072] After output cutoff control is performed in step ST13, the charge / discharge control unit 91a determines the presence of water at predetermined intervals in step ST21. If water is not detected, the process returns to step ST11, where normal output control is performed. If water is detected in step ST21, the process proceeds to step ST22.

[0073] In step ST22, the charge / discharge control unit 91a determines whether the number of water immersion events (i) is greater than or equal to a predetermined number (N). If i is less than N, the process returns to step ST21, where the determination process in step ST21 is repeated. If i is greater than or equal to N, the process proceeds to step ST23.

[0074] In step ST23, the charge and discharge control unit 91a sends a blow signal to the SCP 95 to blow the SCP 95. When the SCP 95 is blown, the battery pack 1 does not output power to the outside unless the SCP 95 is replaced, that is, it is substantially unable to output power.

[0075] According to the second action example, output cut-off control is performed when water immersion is detected, thereby ensuring the safety of the battery pack 1. On the other hand, the water immersion detection sensors 80a and 80b may be turned on not due to water immersion, but due to noise or the like. If the water immersion detection sensors 80a and 80b are turned on due to noise or the like, there is a high possibility that the conduction is canceled during the period of multiple judgments on whether or not water immersion is present, and therefore the judgment processing of step ST21 is no longer water immersion detection. On the other hand, in the case of water immersion, even if the presence or absence of water immersion is judged multiple times, it is judged that water immersion is present. That is, by appropriately setting the prescribed number of times N (for example, N=5), it is possible to prevent the output cut-off control from continuing due to noise from the outside, and in the case of water immersion, the output cut-off control can be reliably performed, and noise tolerance can be improved. In addition, by melting SCP95, the output of the battery pack 1 can be reliably cut off.

[0076] It should be noted that the battery pack 1 can perform one of the processes involved in the first action example and the second action example, or it can be set to be able to set either the process involved in the first action example or the second action example according to the purpose of the battery pack 1, etc.

[0077] Application Examples

[0078] The battery pack 1 according to the present invention can be mounted on an electric tool, an electric vehicle, an electronic device, or the like, or used to supply electric power.

[0079] As a specific example, refer to Figure 12 An example of an electric screwdriver, which is an example of an electric tool to which the present invention can be applied, will be briefly described. An electric screwdriver 431 is equipped with a motor 433 that transmits rotational power to a shaft 434 and a trigger switch 432 operated by the user. A battery pack 430 (battery pack 1 in this embodiment) and a motor control unit 435 according to the present invention are housed within a housing below the handle of the electric screwdriver 431. The battery pack 430 is either built into the electric screwdriver 431 or can be freely attached and detached.

[0080] The battery pack 430 and the motor control unit 435 each include a microcomputer (not shown), and can communicate charge and discharge information of the battery pack 430. The motor control unit 435 can control the operation of the motor 433 and cut off the power supply to the motor 433 in the event of an abnormality such as overdischarge.

[0081] Modifications

[0082] As mentioned above, although one embodiment of the present invention has been specifically described, the content of the present invention is not limited to the above embodiment, and various modifications can be made based on the technical concept of the present invention.

[0083] The shape, size, number, etc. of each structure of the battery pack can be changed without departing from the scope of the present invention. In addition, in the above embodiment, the battery pack 1 may have one water submergence detection sensor or three or more water submergence detection sensors.

[0084] The matters described in the above-mentioned embodiment and modification examples can be combined as appropriate. In addition, the materials, processes, etc. described in the embodiment are only examples, and the content of the present invention is not limited to the exemplified materials, etc.

[0085] Explanation of symbols

[0086] 1. Battery pack; 2. Outer shell; 5. Operating unit; 6. Display unit; 25, 34, O-ring; 30, Inner shell; 31a, Recess; 80a, 80b, Water immersion detection sensor; 85, Water immersion detection unit; 91a, Charge and discharge control unit; 91b, Charge and discharge switch; 401, Battery pack; 405, First circuit substrate; 603, LED substrate; 606, Flexible substrate.

Claims

1. A battery pack comprising: a battery; a first circuit substrate; an outer case; and an inner case disposed inside the outer case. The outer shell includes an outer upper shell, an outer lower shell, and a frame-shaped first elastic member interposed between the outer upper shell and the outer lower shell. The inner housing includes an inner upper housing, an inner lower housing, and a frame-shaped second elastic member interposed between the inner upper housing and the inner lower housing. The battery and the first circuit substrate are housed in the inner housing. A sensor portion for detecting water intrusion is provided between the outer shell and the inner shell. The outer shell and the inner shell each independently form a sealed structure. The outer housing is provided with an operation unit operable from the outside and a display unit for displaying the status of the battery. The sensor unit is arranged near the operation unit and the display unit. A storage portion for storing water is provided in the space between the outer shell and the inner shell. The storage portion is provided at the bottom of a recessed portion on the upper surface of the inner upper shell. The sensor unit is arranged in the storage unit.

2. The battery pack according to claim 1, wherein: The first circuit board is provided with a charge and discharge control unit for controlling the charge and discharge of the battery, and a water submersion detection unit electrically connected to the sensor unit and transmitting water submersion detection information to the charge and discharge control unit.

3. The battery pack according to claim 1 or 2, wherein: An FPC is connected to the first circuit substrate. The sensor portion is disposed on the FPC.

4. The battery pack according to claim 1 or 2, wherein: A plurality of the sensor portions are provided.

5. The battery pack according to any one of claims 1 to 4, wherein: The sensor portion has a structure in which two comb-shaped wiring patterns are formed facing each other, and the distance between adjacent wiring patterns is 0.5 mm.

6. The battery pack according to claim 5, wherein: The sensor unit is arranged on a second circuit substrate that connects the operation unit and the display unit.

7. The battery pack according to claim 1, wherein: The battery pack further includes a charge and discharge control unit for controlling the charge and discharge of the battery and a charge and discharge switch for turning on and off the charge and discharge. The charge and discharge control unit controls the charge and discharge switch to be turned off when it is determined that water is present between the outer case and the inner case.

8. The battery pack according to claim 7, wherein: The charge and discharge control unit determines whether water is present between the outer case and the inner case after a predetermined time has passed after determining that water is present between the outer case and the inner case, and controls the charge and discharge switch to be turned on if it is determined that water is not present.

9. The battery pack according to claim 7, wherein: The charge and discharge switch is connected in series with a fuse with a heater. After determining that water is present between the outer housing and the inner housing, the charge and discharge control unit determines whether water is present a plurality of times at predetermined intervals. When it is determined that the number of times of water intrusion is greater than or equal to a predetermined number, the charge and discharge control unit sends a blow signal to the fuse with heater to blow the fuse with heater. 10 . An electric tool comprising the battery pack according to claim 1 .

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