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Patent Searching and Data


Title:
SERIES CONNECTION OF BATTERY PACKS
Document Type and Number:
WIPO Patent Application WO/2019/236958
Kind Code:
A1
Abstract:
A first battery pack that can be connected to a second battery pack is disclosed. Each battery pack includes a first connection socket and a second connection socket that allow the pair of battery packs to be connected to each other such that the battery cells in each battery pack are connected in series. Each battery pack includes a battery socket accessible through the outer housing of the battery pack. When the pair of battery packs is connected together, only one of the battery sockets is accessible. Each of the battery packs are configured such that the maximum output of the stack of battery packs is limited and only one of the battery sockets is accessible. When connected, the pair of battery packs can be used with power tools designed for either a first voltage and a second voltage higher than the first voltage.

Inventors:
KROUPA RYAN (US)
MORRELL THOMAS D (US)
Application Number:
PCT/US2019/035981
Publication Date:
December 12, 2019
Filing Date:
June 07, 2019
Export Citation:
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Assignee:
BRIGGS & STRATTON CORP (US)
International Classes:
H01M4/04; H01M50/209; H01M50/247; H01M50/51; H01M50/514; H02J7/24
Foreign References:
US20090297892A12009-12-03
US3555395A1971-01-12
US6140799A2000-10-31
Attorney, Agent or Firm:
KUBORN, Joseph D. et al. (US)
Download PDF:
Claims:
CLAIMS

We claim:

1. A battery pack comprising:

an outer housing;

a battery cell contained within the outer housing, the battery cell being connected between a negative terminal and a positive terminal of the battery pack;

a battery socket accessible through the outer housing, the battery socket including a first contact and a second contact; and

a first connection socket and a second connection socket each accessible through the outer housing, wherein the first connection socket is connected to the positive terminal of the battery cell and the second connection socket is connected to the second contact of the battery socket.

2. The battery pack of claim 1 wherein the battery cell includes a plurality of lithium ion battery cells.

3. The battery pack of claim 1 wherein the negative terminal and the positive terminal are sized to be received in the first and second connection sockets when a first battery pack is connected to a second battery pack.

4. The battery pack of claim 3 wherein the negative terminal of the second battery pack is received within the first connection socket of the first battery pack and the positive terminal of the second battery pack is received within the second connection socket of the second battery pack such that the first battery pack can be coupled to the second battery pack

5. The battery pack of claim 4 wherein a first voltage is available across the negative terminal and the positive terminal of the first battery pack when the first and second battery packs are connected and a second voltage is available across the first and second contacts of the battery socket of the first battery pack when the first and second battery packs are connected.

6. The battery pack of claim 5 wherein the second voltage is twice the first voltage.

7. The battery pack of claim 5 wherein the negative terminal and the positive terminal extend from a top face of the housing and the battery socket is recessed into the top face.

8. The battery pack of claim 1 wherein the negative terminal and the positive terminal of the battery pack extend from the outer housing and the first and second connection sockets are recessed into the outer housing.

9. The battery pack of claim 1 wherein the first contact in the battery socket is connected to the negative terminal of the battery pack.

10. The battery pack of claim 5 wherein the outer housing of the first battery pack covers the battery socket of the second battery pack when the first battery pack is connected to the second battery pack.

11. The battery pack of claim 1 wherein the negative terminal and the positive terminal extend from a top face of the outer housing and the battery socket is recessed into the top face.

12. The battery pack of claim 11 wherein the first and second connections sockets are recessed into a bottom face of the outer housing.

Description:
SERIES CONNECTION OF BATTERY PACKS

BACKGROUND

[0001] The present disclosure relates to a rechargeable battery pack that is designed for use with outdoor power tools, such as string trimmers, blowers, lawn mowers, edgers and other similar battery powered tools. More specifically, the present disclosure relates to a battery pack that can be used alone or connected in series with other similar battery packs to increase the output voltage from the stacked battery packs while also limiting the output voltage from the stacked battery packs..

[0002] Many different types of outdoor power tools are available that utilize a rechargeable battery pack to provide power for operating the power tool. Many of these battery packs include a series of lithium ion battery cells joined to each other to create the desired voltage level. As an example, many outdoor power tools utilize a 40 volt battery pack for powering operation of the power tool. One limitation on the size of power tool that can be operated using the 40 volt battery pack is the amount of voltage available from the battery pack. To solve this issue, larger battery packs must be used with larger power tools.

[0003] Larger lithium ion battery packs, such as 80 volt battery packs, are available for operating larger power tools, such as lawn mowers and edgers. Even further, 120 volt battery packs are available that can drive even larger power tools, such as a larger lawn mower or even a lawn tractor. The three different sized battery packs require a home owner or small business owner, such as a lawn care provider, to purchase separate battery packs for powering each different type of power tool. Therefore, the inventors have identified a need for battery packs that can be connected and combined to vary the available voltage to enhance the number of uses for the battery pack across different types of power tools.

SUMMARY

[0004] This Summary is provided to introduce a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter. [0005] The present disclosure is directed to a battery pack that is designed for use with outdoor power equipment, tools or any type of device that can be operated utilizing electric power stored in a battery pack. The battery pack includes an outer housing that surrounds and contains a battery cell. The battery cell can include a single battery cell or a series of battery cells connected together. The battery cell is connected between a negative terminal and a positive terminal of the battery pack such that the voltage generated by the battery cell can be accessed utilizing the positive and negative terminals of the battery pack in a conventional manner.

[0006] The battery pack of the present disclosure further includes a battery socket that is accessible through the outer housing. The battery socket is designed to include at least a first contact and a second contact, although additional contacts could be included. In one exemplary embodiment, the battery socket is recessed into a top surface of the outer housing between the negative and positive terminals of the battery pack.

[0007] In addition to the battery socket, the battery pack includes a first connection socket and a second connection socket that are each accessible through the outer housing. The first connection socket is connected to the positive terminal of the battery cell while the second connection socket is connected to the second contact of the battery socket. The first and second connection sockets are designed and sized such that the first and second connection sockets can receive the positive and negative terminals of a second battery pack that has the identical configuration as the first battery pack to allow the first battery pack and a second battery pack to be connected to each other. In one exemplary embodiment, both of the first and second connection sockets are recessed into a bottom surface of the outer housing.

[0008] The battery pack is designed such that when a first battery pack and a second battery pack are connected to each other, the negative terminal of the second battery pack is received within the first connection socket of the first battery pack and the positive terminal of the second battery pack is received within the second connection socket of the first battery pack. When the first and second battery packs are connected, a first voltage is available between the negative terminal and the positive terminal of the first battery pack and a second voltage is available across the first and second contacts of the battery socket of the first battery pack. The second voltage is twice the first voltage since the battery cells of the first and second battery packs are connected to each other in series when the first and second battery packs are connected. [0009] When the first and second battery packs are connected to each other, the bottom surface of the first battery pack covers the battery socket of the second battery pack such that only the first battery pack can be used to power equipment or tools. The physical configuration of the battery packs allows for ease of connection to each other and limits the available connections to equipment and tools.

[0010] The battery pack constructed in accordance with the present disclosure can support multiple connections to other battery packs. When three or more battery packs are connected to each other, only the positive and negative terminals and the battery socket of one of the battery packs is accessible and the output voltage is limited to twice the output voltage of the battery cells contained in each battery pack. In this manner, the battery pack of the present disclosure limits the maximum output voltage from a series of connected battery packs.

[0011] Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The drawings illustrate the best mode presently contemplated of carrying out the disclosure. In the drawings:

[0013] Fig. 1 is a schematic illustration of a battery pack constructed in accordance with an exemplary embodiment of the disclosure;

[0014] Fig. 2 is a schematic illustration of two battery packs connected together in series to increase the output voltage from the combination;

[0015] Fig. 3 is a schematic illustration of three battery packs connected together where the output voltage of the combination of battery packs is limited;

[0016] Fig. 4 is a perspective view of a pair of battery packs constructed in accordance with an exemplary embodiment connected together;

[0017] Fig. 5 is a front perspective view of the coupled battery packs shown in Fig. 4; and

[0018] Fig. 6 includes a front perspective view of an embodiment of a battery pack including a handle to protect the series of contacts formed in the battery socket on the battery pack and a comparison to a larger battery pack. DET AILED DESCRIPTION

[0019] Fig. 1 illustrates a battery pack 10 constructed in accordance with one

embodiment of the present disclosure. The battery pack 10 includes an outer housing 12 that provides the desired shape and size for the battery pack 10. The outer housing 12 is typically formed from a durable, plastic material that both protects the internal components of the battery pack 10 and provides for connection terminals and sockets for connecting the battery to the power tools. In the embodiment shown in Fig. 1, the battery pack 10 is a 40 volt battery pack, although other sized battery packs are contemplated as being within the scope of the present disclosure.

[0020] The battery pack 10 includes a series of battery cells that are schematically shown in Fig. 1 as a single battery cell 14. The individual cells within the battery cell 14 in one embodiment are lithium ion battery cells that each are capable of producing approximately 3.6 volts and are connected in a series configuration within the battery pack 10 to create the maximum 40 volt output. The battery cell 14 includes a negative end 16 and a positive end 18 with a 40 volt potential across the two ends. The negative end 16 is connected to the negative terminal 20 of the battery pack 10 while the positive end 18 is connected to the positive terminal 22 of the battery pack 10. The negative terminal 20 and positive terminal 22 provide the required connections to the internal battery cell 14 when the battery pack 10 is being used to power a tool requiring a 40 volt output battery.

[0021] In the embodiment shown in Fig. 1, the battery pack 10 includes the plurality of lithium ion battery cells that can be repeatedly charged and discharged to operate a power tool that is designed and configured to operate on 40 volts. Although the single battery pack 10 is useful in operating power tools that are designed for 40 volts, other larger power tools require an 80 volt battery pack to operate. For this reason, the battery pack 10 shown in Fig. 1 has been designed with additional components, connectors and features such that a pair of battery packs 10 can be joined in series to create an 80 volt output voltage as will be described in greater detail below.

[0022] In the battery pack 10 shown in Fig. 1, the battery pack includes a battery socket

24 that is recessed or flush with a top face 25 of the outer housing 12. The battery socket 24 is designed to allow the battery pack to be used in not only a 40 volt application but also in an 80 volt application when a pair of the battery packs 10 are connected in series. The battery socket 24 includes a negative contact 26 and a positive contact 28. A pair of center contacts 30 and 32 is located between the negative contact 26 and positive contact 28 such that the battery socket 24 includes four separate contacts in the exemplary embodiment shown.

[0023] The battery pack 10 includes a pair of connection sockets 34, 36 that allow the battery pack 10 to connect to another battery pack in the manner to be described below. In an exemplary embodiment of the disclosure, both the first connection socket 34 and the second connection socket 36 are recessed or flush with a bottom face 37 of the outer housing 12. The first connection socket 34 is internally connected directly to the positive end 18 of the battery cell 14 while the second connection socket 36 is internally connected directly to the positive contact 28 of the battery socket 24. When the battery pack 10 is used alone as shown in Fig. 1, the first and second connection sockets 34 and 36 are not used and may be covered by a protective plug or shield. In addition, when the battery pack 10 is used alone, the battery socket 24 is not“active” since while the negative contact 26 is connected to the negative terminal 20, the positive contact 28 is floating and is not connected to any source of positive voltage. It is contemplated that the battery socket 24 could be covered when the battery pack 10 is used alone to prevent dust or dirt from accumulating on the contacts.

[0024] Referring now to Fig. 2, thereshown is an exemplary embodiment in which a first battery pack 10A and a second battery pack 10B are connected to each other. Since the battery packs 10A and 10B are identical to each other, common reference numerals are used to describe the common components.

[0025] As shown in Fig. 2, the battery socket 24 of the upper battery pack 10A is exposed while the battery socket 24 of the lower battery pack 10B is covered by the bottom face 37 of the outer housing 12 of the upper battery pack 10A and is not accessible. When the two battery packs are joined as shown in Fig. 2, the positive end 18 of the internal battery cell 14 in the first battery pack 10A is connected to the negative end 16 of the internal battery cell 14 in the second battery pack 10B through the interconnection between the first connection socket 34 of the upper battery pack 10A being joined to the negative terminal 20 of the lower battery pack 10B. Thus, the 40 volt output from the battery cell 14 in the first battery pack 10A is connected to the negative end of the battery cell 14 in the second battery pack 10B. In this manner, the two battery cells 14 are connected in series such that the output voltage available at the positive end

volts, which is the combination of the 40 volt battery cells in the two battery packs.

[0026] As can be seen in Fig. 2, the positive end 18 of the series connection of the battery cells 14 is internally connected to the positive terminal 22 of the lower, second battery pack 10B. The positive terminal 22 of the second battery pack 10B is connected to the second connection socket 36 of the upper, first battery pack 10A. As described previously, the second connection socket 36 of the first battery pack 10A is directly connected to the positive contact 28 in the battery socket 24 of the first battery pack 10A such that a voltage potential of 80 volts is present between the negative contact 26 and positive contact 28 of the first battery pack 10A. Thus, when the two battery packs are joined as shown in Fig. 2, an 80 volt voltage difference is available between the contacts 26 and 28 of the first battery pack 10A. At the same time, a 40 volt output is still available between the negative terminal 20 and positive terminal 22 of the same first battery pack 10A. Thus, the series connection of the two battery packs 10A and 10B can be used to power either a 40 volt power tool or an 80 volt power tool while the battery packs are connected to each other.

[0027] Fig. 3 illustrates an embodiment in which three separate battery packs 10A, 10B and 10C are connected together. In the embodiment shown, the three battery packs are stacked on top of each other, although it should be understood that the orientation of the battery packs could be changed such that the battery packs would be side-by-side or that the battery pack 10A would be the bottom battery pack.

[0028] In the embodiment shown in Fig. 3, each of the individual battery packs are identical as described previously. As with the embodiment shown in Fig. 2, the battery socket 24 of each of the battery packs 10B and 10C are covered by the lower face surface of the outer housing 12 of the battery pack connected thereto. In accordance with the design of the present disclosure, the internal battery cells 14 are connected in series across the three battery packs. In such connection, the voltage at the positive end 18 of the battery cell 14 in the third battery pack 10C can be as high as 120 volts. However, this voltage is not accessible when the battery packs are connected as shown since the positive contact 28 located within the battery socket 24 of the second, middle battery pack 10B is shielded by the bottom face of the outer housing 12 of the first battery pack 10A. Thus, when additional battery packs, such as the third battery pack 10C, are added to the stack, the additional battery packs do not change the output voltage available at the positive contact 28 of the first battery pack 10A, which is the only battery socket 24 that is accessible. In this manner, battery packs can be stacked together without affecting the maximum 80 volt output available at the battery socket 24.

[0029] As can be understood by Figs. 1-3, the design and configuration of each of the individual battery packs 10 allows each of the individual battery packs to be used to supply either a 40 volt output across the positive and negative terminals 20, 22 or an 80 volt output to be available across the contacts 26, 28 of the battery socket 24 of the upper battery pack 10A when two or more battery packs are connected, such as shown in Figs. 2 and 3. The configuration and connection of the 40 volt battery packs allows a single battery pack to be used to power a 40 volt handheld device or a pair of battery packs can be combined to power an 80 volt power tool.

When combined, the combination can also still be used to power a 40 volt power tool.

[0030] Fig. 4 illustrates one embodiment of a specific configuration of the battery packs

10, which are illustrated by a pair joined battery packs 10A and 10B. The embodiment shown in Fig. 4 generally corresponds to the configuration shown in Fig. 2 where Fig. 4 illustrates one possible configuration for the outer housing 12 of each of the battery packs 10. Although one type of configuration for the outer housing 12 is illustrated, along with a location for the positive and negative terminals and the battery socket, it should be understood that various different configurations can be utilized while operating within the scope of the present disclosure. In the embodiment shown in Fig. 4, an adapter 40 is used to join the first battery pack 10A to the second battery pack 10B. The adapter 40 includes a series of contacts 42 and a tool interface 44. The tool interface 44 provides a plug like connector for a power tool. The adapter 40 includes a front connector 46 that allows the first and second battery packs 10A, 10B to be joined to each other in a similar manner as graphically illustrated in Fig. 2.

[0031] Fig. 5 is another view of the embodiment shown in Fig. 4 in which the design of the outer housing is modified. As can be seen in Fig. 5, the combination of the two battery packs 10A, 10B can have a form factor similar to the form factor of a single 80 volt battery pack such that the combination of the two battery packs 10A, 10B can fit in a location designed for a single 80 volt battery pack.

[0032] Fig. 6 illustrates another possible configuration for the battery pack 10. In the embodiment shown in Fig. 6, a handle 50 can be attached to the battery pack 10 for use in carrying the battery pack 10. In the embodiment shown, the handle 50 is formed from a durable plastic material and covers the battery socket on the top face of the outer housing when in use. The handle 50 can be selectively removed utilizing a pair of release tabs 52 located on each side of the handle 50. When the handle 50 is removed, the battery socket is available such that the 40 volt battery pack 10 can be connected to another 40 volt battery pack and the 80 volt combined output voltage can be used to power tools having an 80 volt socket. Also shown in Fig. 6 is a conventional 80 volt battery pack 60. The handle 50 is designed such that the height of the combination of the battery pack 10 and the handle 50 approximates the height of the 80 volt battery pack 60.

[0033] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims _