Battery pack

Abstract

A battery pack includes a housing forming a cavity and a plurality of battery cells disposed within the cavity and configured to be capable of supplying power to an electrical device. The battery pack further includes a circuit board disposed within the housing and including a plurality of electrical components, and a heat sink partially formed within the housing and in direct contact with the heat generating components of the circuit board.

Description

Technical Field

[0001] The present invention relates to battery packs, and more particularly to heat sinks used in battery packs. Summary of the Invention

[0002] Lithium-ion batteries can generate heat during charging and discharging due to the electrochemical reactions driving the battery and the current flowing through the electronic components. Overheating can lead to several complex problems, including thermal runaway. Power tool batteries are particularly vulnerable to overheating due to the large currents drawn by power tools and the compact nature of the battery's electronics and terminals.

[0003] In one aspect, this application provides a battery pack for a power tool, the battery pack including a housing forming a cavity and at least one terminal configured to electrically connect the battery pack to the power tool. The battery pack also includes a plurality of battery cells disposed within the cavity and configured to supply power to the power tool. The battery pack further includes a circuit board disposed within the housing, the circuit board including a plurality of electrical components. The battery pack also includes a heat sink partially formed within the housing and in direct contact with heat-generating components of the circuit board.

[0004] In one aspect, the heat sink further includes a first plurality of fins extending in a first direction and a second plurality of fins extending in a second direction different from the first direction, the second plurality of fins extending away from the housing toward the circuit board and into the cavity. In one aspect, the heat sink further includes a first leg, a second leg, and a third leg, wherein the third leg includes the first plurality of fins and the second plurality of fins. In one aspect, the third leg is formed within the housing such that the top side of the third leg is completely surrounded by the housing, and the bottom side of the third leg is exposed to the cavity of the housing. In one aspect, the second leg is enclosed in the housing such that the second leg is not directly exposed to the cavity or ambient air. In one aspect, the first leg and the third leg are parallel to each other, while the second leg is perpendicular to the first leg and the third leg. In one aspect, the first direction is the same as the extension direction of the third leg, while the second direction is inclined relative to the first direction. In one aspect, the first leg is exposed to the cavity and in contact with the heat-generating component.

[0005] In one aspect, a portion of the radiator is exposed to the ambient air surrounding the battery pack. In another aspect, this portion of the radiator is exposed in a recess formed in the housing, which opens to the ambient air. In yet another aspect, the recess is sized to prevent a user from approaching it.

[0006] In one aspect, the radiator does not come into contact with or is not exposed to ambient air surrounding the battery pack. In another aspect, the housing provides an air inlet and an air outlet, thereby allowing an airflow path to be formed through the cavity from the air inlet to the air outlet, wherein the airflow path passes through the radiator. In another aspect, a fan is disposed within the housing and configured to form an airflow path.

[0007] In one aspect, the housing includes a first housing portion and a second housing portion coupled to the first housing portion, wherein the first housing portion and the second housing portion form a cavity. In one aspect, the heat sink further includes a first leg, a second leg, and a third leg, wherein the third leg includes a first plurality of fins and a second plurality of fins extending in different directions. In one aspect, the third leg is formed within the first housing portion such that the top side of the third leg is flush with the first housing portion and exposed to ambient air, and the bottom side of the third leg is flush with the first housing portion and exposed to the cavity of the housing. In one aspect, the second leg is enclosed within the first housing portion such that the second leg is not directly exposed to the cavity or ambient air. In one aspect, the first leg and the third leg are parallel to each other, while the second leg is perpendicular to the first leg and the third leg. In one aspect, the first leg is exposed to the cavity and contacts a heat-generating component of the circuit board.

[0008] Other aspects of the invention will become apparent from the detailed description and accompanying drawings. Attached Figure Description

[0009] Figure 1 This is a perspective view of a battery pack according to an embodiment of this application.

[0010] Figure 2 According to some embodiments Figure 1 A three-dimensional view of the rear of the battery pack.

[0011] Figure 3 According to some embodiments Figure 1 An exploded view of the battery pack, showing the radiator attached to the first housing section of the housing.

[0012] Figure 4 The battery pack according to some embodiments Figure 2 The cross-sectional view of line 4-4 shows the airflow path within the casing.

[0013] Figure 5 yes Figure 1 An enlarged perspective view of the battery pack shows the airflow path according to another embodiment of this application.

[0014] Figure 6 According to some embodiments Figure 1 A three-dimensional view of the radiator, showing multiple fins.

[0015] Figure 7 According to some embodiments Figure 4 An enlarged view of the battery pack shows the heat sink housed within the casing.

[0016] Figure 8 yes Figure 4 An enlarged view of the battery pack shows a heat sink according to another embodiment of this application.

[0017] Before explaining any embodiment in detail, it should be understood that the embodiments described herein are not limited in their application to the details of the construction and arrangement of the components set forth in the following description or shown in the following drawings. This application is capable of having other embodiments and can be practiced or performed in various ways. Moreover, it should be understood that the wording and terminology used herein are for descriptive purposes and should not be considered limiting.

[0018] Features shown or described as part of one embodiment may be used in conjunction with another embodiment to produce yet another embodiment. Therefore, the invention is intended to cover these modifications and variations falling within the scope of the appended claims and their equivalents. Numerical and alphabetic designations are used to refer to features in the drawings in the detailed description. The same or similar designations in the drawings and specification are used to denote the same or similar portions of the embodiments described herein.

[0019] As used herein, the terms “first,” “second,” and “third” are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of a single component. The singular forms “a,” “an,” and “the” include plural references unless the context clearly indicates otherwise. The terms “connected,” “fixed,” “attached,” etc., refer to direct connection, fixation, or attachment, as well as indirect connection, fixation, or attachment via one or more intermediate components or features, unless otherwise specified herein. As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “having,” or any other variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, article of manufacture, or apparatus that comprises a list of features is not necessarily limited to those features but may include other features not expressly listed or inherent to such process, method, article of manufacture, or apparatus.

[0020] The following description of specific embodiments illustrates the benefits, other advantages, and solutions to problems. However, the benefits, advantages, solutions to problems, and any features that may cause any benefit, advantage, or solution to appear or become more significant should not be construed as key, essential, or fundamental features of any or all claims. Detailed Implementation

[0021] Figure 1 and Figure 2 A battery pack 10 according to some embodiments is shown. The battery pack 10 can be connected to and operated to power electrical devices, such as: handheld power tools (e.g., drills, fasteners, saws, pipe cutters, grinders, nailers, staplers, vacuum cleaners, etc.); motor-driven power tools (e.g., cutting saws, miter saws, table saws, core drills, augers, crushers, hydraulic breakers, compactors, vibrators, compressors, drain cleaners, welding machines, cable pullers, pumps, etc.); outdoor tools (e.g., chainsaws, rope trimmers, hedge trimmers, blowers, lawnmowers, ride-on lawnmowers, etc.); other motor-driven devices (e.g., vehicles, multi-purpose carts, material handling trolleys, etc.); and non-motor-driven electrical devices (e.g., power supplies, lights, AC / DC adapters, generators, personal electronic devices, etc.), any of which may now be referred to herein as "electrical devices". Furthermore, in other embodiments, the battery pack 10 can be connected to and operated to power other electrical devices. The battery pack 10 can be removed from the electrical device and can be recharged by a battery charger (not shown).

[0022] Battery pack 10 includes battery chemicals such as lead-acid, nickel-cadmium (“NiCd”), nickel metal hydride (“NiMH”), lithium (“Li”), lithium-ion (“Li-ion”), other lithium-based chemicals, or other rechargeable or non-rechargeable battery chemicals. In some embodiments, battery pack 10 may include Li, Li-ion battery chemicals, or other lithium-based chemicals and may provide an average discharge current equal to or greater than about 20 A. In one example, battery pack 10 may include lithium cobalt (“Li-Co”), lithium manganese (“Li-Mn”) spinel, Li-Mn nickel, or other lithium metal chemicals.

[0023] Battery pack 10 has a nominal voltage. In some embodiments, battery pack 10 may have a nominal voltage of approximately 9.6 V. In other embodiments, battery pack 10 may have a nominal voltage of up to approximately 50 V. In some embodiments, battery pack 10 may have a nominal voltage of approximately 21 V. In other embodiments, battery pack 10 may have a nominal voltage of approximately 28 V. Furthermore, in other embodiments, battery pack 10 may have a nominal voltage of, for example, 12 V, 14.4 V, 18 V, 24 V, 40 V, or 80 V, for powering an electrical device and being charged by a battery charger (not shown).

[0024] Continue to refer to Figure 1 and Figure 2The battery pack 10 includes a housing 14 having a first housing portion 18 and a second housing portion 22. The battery pack 10 also includes an electrical interface 24 having one or more terminals 26 configured to engage and electrically connect to an electrical device. The terminals 26 are accessible from the outside of the housing 14 to allow direct engagement of the electrical device with the electrical interface 24. The first housing portion 18 and the second housing portion 22 are joined together via a plurality of fasteners 28. An O-ring (not shown) is provided at the interface between the first housing portion 18 and the second housing portion 22 to prevent dust and other debris from entering the housing 14. Specifically, when the first and second housing portions 18, 22 are joined together, the O-ring is partially received within a groove 29 extending around the periphery of the second housing portion 22, and further received within a corresponding groove (not shown) extending around the periphery of the first housing portion 18. Although fasteners 28 are used to join the first and second housing portions 18, 22 together in the illustrated embodiment, in other embodiments, the first housing portion 18 and the second housing portion 22 may be joined together via adhesives, tapes, fasteners, tabs, or any combination thereof. The battery pack 10 also includes a locking mechanism 20 configured to selectively connect the battery pack 10 to an electrical device.

[0025] refer to Figure 3 The housing 14 defines an inner cavity 30. The housing 14 (more specifically, the cavity 30) receives and supports a battery cell assembly 34. The battery cell assembly 34 includes a plurality of battery cells 38 and a support structure 42 that receives and supports the plurality of battery cells 38. The plurality of battery cells 38 have the chemical composition and nominal voltage as described above. In the illustrated embodiment, the housing 14 is shaped and sized to receive twenty battery cells 38, while in other embodiments, the housing 14 may receive different predetermined numbers of battery cells 38 (e.g., ten, thirty, forty, one hundred, etc.). In some embodiments, the battery cell assembly 34 may include two or more battery cells 38. The battery cells 38 may be connected in series, in parallel, or in a series-parallel combination to provide the desired electrical characteristics of the battery pack 10 (e.g., nominal voltage, current output, current capacity, power capacity, etc.).

[0026] Continue to refer to Figure 3The housing 14 substantially surrounds a support circuit or circuit board 46 electrically connected to one or more terminals 26. The circuit board 46 is positioned above and supported by the battery cell assembly 34, such that it is located within a first housing portion 18 of the housing 14. Specifically, the circuit board 46 is supported on top of a support structure 42 of the battery cell assembly 34 and adjacent to the first housing portion 18. The circuit board 46 includes a microcontroller or microprocessor and is configured to provide operational control of the battery pack 10 and monitor various characteristics (e.g., voltage, temperature, etc.) of each individual battery cell 38. For example, the circuit board 46 controls electrical components within the battery pack 10 to control the charging and discharging of the battery cells 38. Simply put, the circuit board 46 can supply power to electrical devices via the battery cells 38. That is, the circuit board 46 can communicate with electrical devices, a battery charger (not shown), and can provide these devices with information about one or more battery characteristics or conditions of the battery pack 10, such as nominal voltage, temperature, chemical properties, and / or other similar characteristics.

[0027] refer to Figures 1 to 4 The housing 14 also includes an air inlet 47, an air outlet 48, and a fan 49, which are configured to form an airflow path AF within the cavity 30 of the housing 14. In some embodiments, the battery pack 10 may include multiple conduits or channels disposed within the housing 14 to guide the airflow path AF over specific electronic components (e.g., terminals, microprocessors, battery cells, MOSFETs, etc.). The battery pack 10 may also include multiple fans; for example, a first fan may be used to draw in ambient air along the airflow path AF through the air inlet 47, while a second fan may be used to guide the airflow path AF toward the air outlet 48. The fan 49 may also be operatively controlled by a circuit board 46. For example, in some embodiments, the fan 49 may be used to guide the airflow path AF to specific components or areas of the circuit board 46 and the battery cell assembly 34 based on signals received by the circuit board 46.

[0028] refer to Figure 3 and Figure 4 The battery pack 10 may also include a heat sink 50 and a terminal contact plate 54 adjacent to the heat sink 50. The terminal contact plate 54 supports the terminals 26 and electrically connects the terminals 26 to the circuit board 46. That is, the terminal contact plate 54 is in direct (or thermal) contact with the circuit board 46 and is adjacent to the heat sink 50. The heat sink 50 is also in direct (or thermal) contact with heat-generating components of the circuit board 46 (e.g., multiple MOSFETs 58, resistors, transistors, capacitors, inductors, sensors, etc.). Plate 57 ( Figure 3 and Figure 7A plate 57 can be connected between multiple MOSFETs 58 and the heat sink 50, thereby allowing thermal conduction between the MOSFETs 58 and the heat sink 50 without creating an electrical connection. Therefore, in some embodiments, the plate 57 is made of a thermally conductive and electrically insulating material (e.g., aluminum nitride, carbon fiber composite, diamond-like carbon, etc.). In some embodiments, the plate 57 may be made of a conductive material and contact the MOSFETs 58 without causing a short circuit.

[0029] Continue to refer to Figure 3 and Figure 4 The heat sink 50 can extend over some electrical components of the circuit board 46, allowing it to capture and dissipate heat from the circuit board 46 to prevent accidental damage from overheating. The heat sink 50 can be made of various thermally conductive materials (e.g., aluminum, copper, metal alloys, composite alloys, etc.).

[0030] refer to Figures 3 to 5 The heat sink 50 is disposed within the housing 14, and more specifically, may be directly molded within the first housing portion 18 adjacent to the circuit board 46. The heat sink 50 may be formed as an integral component having a first leg 56, a second leg 60, and a third leg 64. In other embodiments, the heat sink 50 may be formed as a multi-piece component. The first leg 56 contacts the circuit board 46 via a plate 57, while the third leg 64 is at least partially formed within the first housing portion 18 and disposed above the circuit board 46. The second leg 60 is located between the first leg 56 and the third leg 64. Moreover, the second leg 60 is completely disposed within and surrounded by the first housing portion 18. The first leg 56 and the third leg 64 are parallel to each other, and the second leg 60 is perpendicular to the first leg 56 and the third leg 64. Although the heat sink 50 of the illustrated embodiment is molded (via an overmolding process) into the first housing portion 18, other fastening methods (e.g., screws, adhesives, magnets, etc.) can be used to attach the heat sink 50 to the first housing portion 18.

[0031] refer to Figures 4 to 6The third leg 64 of the heat sink 50 includes a first plurality of fins 66 extending in a first direction and a second plurality of fins 70 extending in a second direction different from the first direction. The first direction is the same as the direction in which the third leg 64 extends, while the second direction curves downward toward the circuit board 46. That is, the first plurality of fins 66 are at least partially formed within the first housing portion 18, while the second plurality of fins 70 are disposed outside the first housing portion 18. Specifically, the top sides of the first plurality of fins 66 are disposed within the first housing portion 18 of the housing, while the bottom sides of the first plurality of fins 66 are flush with the first portion 18 and exposed to the cavity 30. Furthermore, the second plurality of fins 70 extend out of the first housing portion 18 and are disposed within the cavity 30 of the housing 14. The second plurality of fins 70 are closer to the circuit board 46 than the first plurality of heat sink fins 66. In other embodiments, the heat sink 50 may also include other fins extending outward from the cavity 30 to the outside of the battery pack 10. Furthermore, in other embodiments, each of the legs 56, 60, and 64 may include additional outwardly extending fins.

[0032] Continue to refer to Figures 4 to 6 The airflow path AF passes through the circuit board and through the first and second multiple fins 66, 70 ( Figure 4 The airflow path AF provides heat dissipation to the circuit board 46 and the heat sink 50 through convection of the first and second plurality of fins 66, 70. Figure 6 As shown, the first leg 56 includes a hole 74, and the second leg 60 includes a hole 78. Holes 74 and 78 facilitate mounting the heat sink 50 to the circuit board 46 and the first housing portion 18. In other embodiments, holes 74 and 78 allow an airflow path AF to travel through them, thereby providing additional heat collection and dissipation. Furthermore, in other embodiments, holes 74 and 78 can serve as additional inlets and outlets to allow the airflow path AF to travel from inside the housing 14 to the ambient air outside the housing 14. Figure 5 ).

[0033] refer to Figure 7The first housing portion 18 of the housing 14 includes a recess 84 disposed adjacent to the heat sink 50. Specifically, the recess 84 extends along the first leg 56 and the second leg 60 of the heat sink 50, thereby allowing the first leg 56 and the second leg 60 to effectively dissipate heat into the ambient air via the recess 84 through the first housing portion 18. Essentially, only a thin portion 80 of the first housing portion 18 separates the heat sink 50 from the ambient air. The thin portion 80 may be thinner than the remaining portion of the first housing portion 18. In some embodiments, the thin portion 80 may be made of a thermally conductive material to facilitate heat transfer between the heat sink 50 and the ambient air outside the battery pack 10. In some embodiments, a portion of the heat sink is exposed in the recess 84, which opens to the ambient air. The size of the recess may be configured to prevent a user from approaching it with his / her fingers. In some embodiments, the thin portion 80 may be omitted, thereby exposing the heat sink.

[0034] Figure 8 A heat sink 150 similar to heat sink 50 is shown. However, heat sink 150 is at least partially exposed to ambient air outside the battery pack 10. As shown, heat sink 150 includes a first bridging fin 174 and a second bridging fin 178 extending from heat sink 150 to ambient air outside the housing 14. Specifically, the first bridging fin 174 extends from heat sink 150 to recess 84 such that the first bridging fin 174 is at least partially flush with the exterior of the first housing portion 18 and in direct contact with ambient air. Similarly, the second bridging fin 178 extends from heat sink 150 through the first housing portion 18 such that the second bridging fin 174 is at least partially flush with the exterior of the first housing portion 18 and in direct contact with ambient air.

[0035] While various aspects of the invention have been described in detail with reference to certain embodiments, variations and modifications exist within the scope and spirit of one or more of the described individual aspects. Various features of the invention are set forth in the appended claims.

Claims

1. A battery pack for a power tool, the battery pack comprising: The housing forms a cavity; At least one terminal, the at least one terminal being configured to electrically connect the battery pack to the power tool; Multiple battery cells are disposed within the cavity and configured to supply power to the power tool; A circuit board, disposed within the housing, located on top of the plurality of battery cells, and comprising a plurality of electrical components; and A heat sink, which is at least partially formed within the housing and is in direct contact with the heat-generating components of the circuit board.

2. The battery pack according to claim 1, wherein, The heat sink further includes a first plurality of fins and a second plurality of fins, the first plurality of fins extending along a first direction, the second plurality of fins extending along a second direction different from the first direction, the second plurality of fins extending away from the housing toward the circuit board and into the cavity.

3. The battery pack according to claim 2, wherein, The radiator also includes a first leg, a second leg, and a third leg, wherein the third leg includes the first plurality of fins and the second plurality of fins.

4. The battery pack according to claim 3, wherein, The third leg is formed within the housing such that the top side of the third leg is completely surrounded by the housing, and the bottom side of the third leg is exposed to the cavity of the housing.

5. The battery pack according to claim 3, wherein, The second leg is enclosed in the housing so that the second leg is not directly exposed to the cavity or ambient air.

6. The battery pack according to claim 3, wherein, The first leg and the third leg are parallel to each other, while the second leg is perpendicular to the first leg and the third leg.

7. The battery pack according to claim 3, wherein, The first direction is the same as the extension direction of the third leg, while the second direction is inclined relative to the first direction.

8. The battery pack according to claim 3, wherein, The first leg is exposed to the cavity and in contact with the heating element.

9. The battery pack according to claim 1, wherein, A portion of the radiator is exposed to the ambient air surrounding the battery pack.

10. The battery pack according to claim 9, wherein, The portion of the radiator is exposed in a recess formed in the housing, the recess being open to ambient air.

11. The battery pack according to claim 10, wherein, The recess is sized to prevent the user from approaching it.

12. The battery pack according to claim 1, wherein, The heat sink does not come into contact with or is not exposed to ambient air around the battery pack.

13. The battery pack according to claim 1, wherein, The housing provides an air inlet and an air outlet, thereby allowing an airflow path to be formed through the cavity from the air inlet to the air outlet, wherein the airflow path passes through the radiator.

14. The battery pack according to claim 13, wherein, A fan is provided in the housing, and the fan is configured to form the airflow path.

15. The battery pack according to claim 1, wherein, The housing includes a first housing portion and a second housing portion connected to the first housing portion, wherein the first housing portion and the second housing portion form the cavity.

16. The battery pack according to claim 15, wherein, The radiator also includes a first leg, a second leg, and a third leg, wherein the third leg includes a first plurality of fins and a second plurality of fins extending in different directions.

17. The battery pack according to claim 16, wherein, The third leg is formed within the first housing portion such that the top side of the third leg is flush with the first housing portion and exposed to ambient air, and the bottom side of the third leg is flush with the first housing portion and exposed to the cavity of the housing.

18. The battery pack according to claim 16, wherein, The second leg is enclosed within the first housing portion, so that the second leg is not directly exposed to the cavity or ambient air.

19. The battery pack according to claim 16, wherein, The first leg and the third leg are parallel to each other, while the second leg is perpendicular to the first leg and the third leg.

20. The battery pack according to claim 16, wherein, The first leg is exposed to the cavity and in contact with the heating element of the circuit board.

Images