Patent Description:
<CIT> describes a power tool battery pack that includes a lower side case, an upper side case fixed to the lower side case, a battery cell in the lower side case, and a circuit board connected to the battery cell. A plurality of electrical signal terminals are arranged in parallel on the circuit board. The circuit board includes at least one slit between adjacent pairs of the plurality of signal terminals to make it difficult for any water that reaches the circuit board to electrically short two of the signal terminals together. Alternatively or additionally, a wall structure is provided between the terminals to reduce the likelihood that water reaching one of the signal terminals can electrically connect two of the signal terminals.

<CIT> describes a combination of an electric tool and a battery pack. The battery pack comprises a plurality of batteries, a circuit board, and an electronic control assembly. The electronic control assembly is arranged on the circuit board, which is connected with the batteries. The electric tool also comprises a circuit board and an electronic control assembly arranged on its circuit board. The electronic control assemblies in the battery pack and the electric tool can respectively be used for monitoring the state of the battery pack and for performing protection control on the battery pack.

Based on the use requirement for portability, more and more power tools currently use battery packs as power sources.

The battery packs for supplying power to the power tools mostly use cylindrical lithium cells. Multiple cylindrical lithium cells connected in series and in parallel ensure sufficient electric power output so that the endurance of the power tools is improved.

At present, a cylindrical lithium-ion battery generally includes a cell, that is, a positive electrode sheet, a negative electrode sheet, and a separator are wound so as to form the cell, and an electrolyte, a battery housing, upper and lower insulating gaskets, and a cap are sealed so as to complete the preparation. The power tool is operating while this type of battery is being charged or discharged, resulting in a series of unfavorable factors that affect the service life of the battery. For example, due to inevitable vibration and jitter of the power tool, the internal lithium-ion battery is subjected to constant impacts from external forces such as vibration and jitter at the same time. Solder joints of exposed tabs of a negative electrode and at the bottom of a steel shell are more likely to break due to continuous external impacts, thereby affecting the service life of the cylindrical lithium-ion battery.

The present application provides a battery pack, which has better anti-fall and shock-absorbing effects.

The present application adopts technical solutions defined by the appended claims.

The present application adopts the technical solutions defined by the appended claims so that the charging compatibility of the charging system and the battery pack can be improved.

The present application is described below in detail in conjunction with drawings and embodiments.

As shown in <FIG> and <FIG>, a battery pack <NUM> includes a housing <NUM>, a cell assembly <NUM>, and a battery pack interface <NUM>. A voltage of the battery pack <NUM> is generally <NUM> V, <NUM> V, <NUM> V, <NUM> V, <NUM> V, or <NUM> V. To facilitate the description of technical solutions in the present application, a front side, a rear side, a left side, a right side, an upper side, and a lower side shown in <FIG> are further defined.

The housing <NUM> includes an upper housing <NUM> and a lower housing <NUM> assembled at a boundary surface to form an inner cavity. The housing <NUM> is made of a first material. Specifically, the first material is a thermoplastic material such as polyethylene plastic and polyvinyl chloride plastic. The upper housing <NUM> and the lower housing <NUM> are assembled into the housing <NUM> so as to form the inner cavity for accommodating the cell assembly <NUM>. The housing <NUM> is at least partially formed with a battery pack coupling portion <NUM> configured to connect the battery pack <NUM> to a power tool, and the battery pack <NUM> can be connected to the power tool along a first direction. Specifically, the battery pack coupling portion <NUM> is formed on an upper surface of the housing <NUM>, and the battery pack coupling portion <NUM> can mate with a tool mating portion of the power tool so that the battery pack <NUM> can be detachably attached to the power tool along an installation direction. In some embodiments, the battery pack coupling portion <NUM> is provided with a pair of guide rails.

The cell assembly <NUM> is disposed in the inner cavity formed by the housing <NUM>. The cell assembly <NUM> includes multiple non-cylindrical cell units <NUM>, where the multiple cell units <NUM> are connected in series, in parallel, or in series and in parallel to form the cell assembly <NUM>. In some embodiments, a voltage of a single cell unit <NUM> is <NUM> V. The cell assembly <NUM> further includes a positive terminal <NUM> of the cell assembly and a negative terminal <NUM> of the cell assembly. The positive terminal <NUM> of the cell assembly is connected to at least a positive electrode of the cell unit; and the negative terminal <NUM> of the cell assembly is connected to at least a negative electrode of the cell unit. The positive terminal <NUM> of the cell assembly and the negative terminal <NUM> of the cell assembly are disposed on the same side of the battery pack <NUM>. Specifically, the positive electrode of the cell unit and the negative electrode of the cell unit are disposed on the same side of the battery pack <NUM>. In some embodiments, the positive electrode of the cell unit and the negative electrode of the cell unit are disposed on a front end surface of the battery pack <NUM>. In some other embodiments, the positive electrode of the cell unit and the negative electrode of the cell unit are disposed on a rear end surface of the battery pack <NUM>. In some embodiments, the cell unit <NUM> is a flat pouch-like structure, and the multiple cell units <NUM> are stacked sequentially along an up-and-down direction. The cell unit <NUM> may also be bent into an arc, for example, in a pouch-type battery pack. The cell unit <NUM> further includes a cell housing, and generally an aluminum plastic film is used as the cell housing. It is to be understood that the present application is not limited to the embodiments described herein, and the structure of a cell is not limited herein.

In some embodiments, an energy density (energy/mass of the battery pack) of the cell assembly <NUM> is in a value range of greater than <NUM> Wh/kg. Optionally, the energy density (energy/mass of the battery pack) of the cell assembly <NUM> is in a value range of greater than <NUM> Wh/kg. Optionally, the energy density (energy/mass of the battery pack) of the cell assembly <NUM> is in a value range from <NUM> Wh/kg to <NUM> Wh/kg. Optionally, the energy density (energy/mass of the battery pack) of the cell assembly <NUM> is in a value range from <NUM> Wh/kg to <NUM> Wh/kg. Optionally, the energy density (energy/mass of the battery pack) of the cell assembly <NUM> is in a value range from <NUM> Wh/kg to <NUM> Wh/kg. Optionally, the energy density (energy/mass of the battery pack) of the cell assembly <NUM> is in a value range from <NUM> Wh/kg to <NUM> Wh/kg.

In some embodiments, an internal resistance of the cell of the battery pack <NUM> is less than or equal to <NUM> mΩ. Optionally, the internal resistance of the cell of the battery pack <NUM> is less than or equal to <NUM> mΩ. Optionally, the internal resistance of the cell of the battery pack <NUM> is less than or equal to <NUM> mΩ.

In some embodiments, the battery pack <NUM> has a discharge current of greater than or equal to <NUM> A. Optionally, the battery pack <NUM> has a discharge current of greater than or equal to <NUM> A. Optionally, the battery pack <NUM> has a discharge current of greater than or equal to <NUM> A.

The battery pack interface <NUM> is formed on the upper surface of the housing <NUM>, electrically connected to at least the cell assembly <NUM>, and configured to establish a physical and electrical connection with the power tool. The battery pack interface <NUM> includes a power supply positive interface, a power supply negative interface, and a power supply communication interface. The battery pack outputs electric power through the power supply positive interface and the power supply negative interface, and the battery pack communicates through the power supply communication interface with the power tool or a charger attached to the battery pack. In an embodiment, six battery pack interfaces <NUM> are provided on the housing. It is to be understood that more or fewer battery pack interfaces <NUM> may be provided on the housing <NUM> of the battery pack <NUM> according to an electrical characteristic of the battery pack.

The battery pack interface <NUM> is further provided with a positive terminal <NUM> of the battery pack, a negative terminal <NUM> of the battery pack, and a communication terminal <NUM> of the battery pack. The positive terminal <NUM> of the battery pack is electrically connected to the positive terminal <NUM> of the cell assembly and disposed in the power supply positive interface; the negative terminal <NUM> of the battery pack is electrically connected to the negative terminal <NUM> of the cell assembly and disposed in the power supply negative interface. The positive terminal <NUM> of the battery pack and the negative terminal <NUM> of the battery pack are configured to mate with tool terminals of the power tool so as to output electric power of the cell assembly <NUM> to the power tool. Specifically, the electric power of the cell assembly <NUM> reaches the power tool through the positive terminal <NUM> of the cell assembly and the positive terminal <NUM> of the battery pack and returns to the cell assembly <NUM> through the negative terminal <NUM> of the battery pack and the negative terminal <NUM> of the cell assembly. Therefore, the cell assembly <NUM>, the positive terminal <NUM> of the cell assembly, the positive terminal <NUM> of the battery pack, the negative terminal <NUM> of the battery pack, the negative terminal <NUM> of the cell assembly, and the power tool form a current loop. Moreover, the communication terminal <NUM> of the battery pack is disposed in the power supply communication interface and configured for communication with the connected power tool or charger. As an embodiment of specific structures of the positive terminal <NUM>, the negative terminal <NUM>, and the communication terminal <NUM> of the battery pack, the positive terminal <NUM>, the negative terminal <NUM>, and the communication terminal <NUM> of the battery pack clamp the tool terminals by an elastic force from two sides in a left-and-right direction, respectively. Therefore, the tool terminals of the power tool are guided by the battery pack interface <NUM> of the battery pack to be inserted into the positive terminal <NUM> of the battery pack and the negative terminal <NUM> of the battery pack during the process of installing the battery pack to the power tool so that the tool terminals are clamped by the positive terminal and the negative terminal, and the power tool is electrically connected to the battery pack <NUM>.

In some embodiments, the positive terminal <NUM> of the cell assembly is connected in series between a positive electrode of at least one cell unit and the positive terminal <NUM> of the battery pack; and the negative terminal <NUM> of the cell assembly is connected in series between a negative electrode of at least one cell unit and the negative terminal <NUM> of the battery pack. The cell assembly <NUM> further includes a positive lead-out piece <NUM> and a negative lead-out piece <NUM>, where the positive lead-out piece <NUM> connects the positive terminal <NUM> of the cell assembly to the positive electrode of the cell unit, and the negative lead-out piece <NUM> connects the negative terminal <NUM> of the cell assembly to the negative electrode of the cell unit. To prevent the temperature of the positive lead-out piece <NUM> from rising sharply when the battery pack <NUM> outputs a large discharge current, the positive lead-out piece <NUM> is a metal sheet with a certain width. In this manner, a heat dissipation effect of the positive lead-out piece <NUM> is improved, thereby reducing the heat generation of the battery pack <NUM> in use, improving the safety and reliability of the battery pack <NUM>, and prolonging the service life of the battery pack <NUM>. Specifically, a width of the positive lead-out piece <NUM> is in an interval of <NUM> to <NUM>, and a thickness of the positive lead-out piece <NUM> is in an interval of <NUM> to <NUM>. Optionally, the width of the positive lead-out piece <NUM> is in an interval of <NUM> to <NUM>.

In some other embodiments, the negative connecting piece <NUM> of the battery pack <NUM> is a metal sheet with a certain width so that a heat dissipation effect of the negative lead-out piece <NUM> is improved, thereby reducing the heat accumulation of the battery pack <NUM> in use, improving the safety and reliability of the battery pack <NUM>, and prolonging the service life of the battery pack <NUM>. A width of the negative lead-out piece <NUM> is in an interval of <NUM> to <NUM>, and a thickness of the negative lead-out piece <NUM> is in an interval of <NUM> to <NUM>. Optionally, the width of the negative lead-out piece <NUM> is in an interval of <NUM> to <NUM>. It is to be understood that to improve the heat dissipation effect, the positive lead-out piece <NUM> and the negative lead-out piece <NUM> of the battery pack <NUM> may each be the metal sheet with a certain width. In this embodiment, since the positive terminal <NUM> of the cell assembly and the negative terminal <NUM> of the cell assembly are disposed on the same side of the battery pack <NUM> and the multiple cell units <NUM> included in the cell assembly <NUM> are connected in series, a length of the positive lead-out piece <NUM> is different from a length of the negative lead-out piece <NUM>.

Referring to <FIG>, the cell assembly <NUM> further includes a cell connection piece <NUM>, where the cell connection piece <NUM> is configured to connect adjacent cell units <NUM>. Specifically, the cell connection piece <NUM> is connected to a positive electrode of one cell unit and a negative electrode of another cell unit, and the cell assembly <NUM> includes multiple cell connection pieces <NUM> so that the cell units <NUM> are connected in series. Moreover, the cell connection piece <NUM> has the same width as the positive lead-out piece <NUM> and/or the negative lead-out piece <NUM> so that a heat dissipation effect of the cell connection piece <NUM> is improved, thereby reducing the heat accumulation of the battery pack <NUM> in use, improving the safety and reliability of the battery pack <NUM>, and prolonging the service life of the battery pack. In an embodiment, the cell assembly <NUM> includes at least a first cell and a second cell connected in series, where a negative electrode of the first cell is electrically connected to the negative lead-out piece <NUM>, and a positive electrode of the second cell is electrically connected to the positive lead-out piece <NUM>. Correspondingly, the cell assembly <NUM> further includes at least one cell connection piece <NUM> connected to a positive electrode of the first cell and a negative electrode of the second cell so that the first cell and the second cell are connected in series.

As shown in <FIG> and <FIG>, the battery pack further includes a cover plate <NUM>, a circuit board <NUM>, a first bracket <NUM>, and a second bracket <NUM>.

The cover plate <NUM> is connected to the lower housing <NUM> of the battery pack and the cover plate <NUM> and the lower housing <NUM> form an accommodation space for accommodating the cell assembly <NUM>. In some embodiments, the cover plate <NUM> is detachably connected to the lower housing <NUM> of the battery pack through bolts so as to form the accommodation space for accommodating the cell assembly <NUM>. Similarly, the cover plate <NUM> and the upper housing <NUM> of the battery pack also form an accommodation space for accommodating components such as the positive terminal <NUM> of the battery pack, the negative terminal <NUM> of the battery pack, and the communication terminal <NUM> of the battery pack. Specifically, the cover plate <NUM> has a flat plate-like structure.

The circuit board <NUM> is electrically connected to the cell assembly <NUM> and the battery pack interface <NUM>. Specifically, the circuit board <NUM> is connected in series between the cell assembly <NUM> and the battery pack interface <NUM> and configured to collect an electrical signal related to the battery pack. In this embodiment, in some embodiments, the circuit board <NUM> is connected in series between the cell assembly <NUM> and the communication terminal <NUM> of the battery pack and configured to transmit information of the battery pack through the communication terminal <NUM> of the battery pack to the power tool attached to the battery pack. The information of the battery pack includes the discharge current of the battery pack, the temperature of the cell assembly <NUM> and/or the cell unit <NUM>, the voltage of the cell unit <NUM>, and a value of the internal resistance of the cell unit <NUM>.

The first bracket <NUM> is disposed on an upper side of the lower housing <NUM> and configured to fix the positive terminal <NUM> of the battery pack and the negative terminal <NUM> of the battery pack. Specifically, the first bracket <NUM> is disposed in the accommodation space formed by the cover plate <NUM> and the upper housing <NUM> of the battery pack, that is, the first bracket <NUM> is disposed on an upper side of the cover plate <NUM>. Therefore, the first bracket <NUM> is configured to fix the positive terminal <NUM> and the negative terminal <NUM> of the battery pack at preset positions on the upper side of the cover plate <NUM>. The first bracket <NUM> includes a flat plate portion fixed to an upper surface of the cover plate <NUM>, and the positive terminal <NUM> of the battery pack and the negative terminal <NUM> of the battery pack are fixed to the flat plate portion in an exposed state. Specifically, the first bracket <NUM> further includes a positive terminal portion <NUM> and a negative terminal portion <NUM>, where the positive terminal portion <NUM> is configured to accommodate the positive terminal <NUM> of the battery pack, and the negative terminal portion <NUM> is configured to accommodate the negative terminal <NUM> of the battery pack. In some embodiments, the positive terminal portion <NUM> and the negative terminal portion <NUM> each are a structure with an opening at at least one end along the installation direction of the battery pack so that when the battery pack <NUM> is coupled to the power tool, the positive terminal <NUM> of the battery pack and the negative terminal <NUM> of the battery pack can accommodate the tool terminals, and thus the battery pack is electrically connected to the power tool, so as to output the electric power of the battery pack <NUM> to the power tool.

The second bracket <NUM> is disposed on an upper side of the circuit board <NUM> to fix the circuit board <NUM>. Specifically, the second bracket <NUM> and the circuit board <NUM> are disposed on the upper side of the cover plate <NUM>, that is, the second bracket <NUM> and the circuit board <NUM> are disposed in the accommodation space formed by the cover plate <NUM> and the upper housing of the battery pack. The second bracket <NUM> is further configured to fix the communication terminal <NUM> of the battery pack. Therefore, the second bracket <NUM> includes a communication terminal portion <NUM> configured to support the communication terminal <NUM> of the battery pack. Moreover, the second bracket <NUM> further includes a connection portion <NUM>, where the connection portion <NUM> is a square frame detachably connected to the circuit board <NUM> so that the second bracket <NUM> is detachably connected to the circuit board <NUM>. The connection portion <NUM> is formed with an open region so as to encapsulate the circuit board <NUM>. In this manner, as shown in <FIG>, the circuit board <NUM> may be divided into two regions through the square frame of the connection portion <NUM>, where a region of the circuit board <NUM> on an inner side of the connection portion <NUM> is defined as a first region <NUM>, and a region of the circuit board <NUM> on an outer side of the connection portion <NUM> is defined as a second region <NUM>. Therefore, to improve the waterproof performance of the battery pack, as many electronic elements as possible are encapsulated in the first region <NUM>, and the number of electronic elements accommodated in the first region <NUM> is greater than the number of electronic elements in the second region <NUM>. The connection portion <NUM> is provided, which facilitates the subsequent encapsulation of the electronic elements on the inner side of the connection portion <NUM>, that is, the electronic elements in the first region <NUM> of the circuit board <NUM> in a glue injection manner, so as to improve the waterproof performance of the circuit board <NUM> and improve the reliability of the battery pack.

When the circuit board <NUM> fails, to facilitate maintenance to prolong the service life of the battery pack and reduce the use cost of the battery pack, the circuit board <NUM> can be detached from the battery pack for maintenance. Therefore, the second bracket <NUM> is configured to be detachably connected to the first bracket <NUM> so that the circuit board <NUM> is detachably connected to the first bracket <NUM>. When the circuit board <NUM> fails, the second bracket <NUM> along with the circuit board <NUM> is detached from the first bracket <NUM> so that the circuit board <NUM> is separated from the battery pack, which facilitates the maintenance of the circuit board <NUM>. A detailed description is given below in conjunction with embodiments.

In some embodiments, the first bracket <NUM> further includes a guiding portion <NUM> configured to guide the second bracket <NUM> to be coupled to the first bracket <NUM> along a second direction. In some embodiments, the positive terminal portion <NUM> and the negative terminal portion <NUM> of the first bracket <NUM> are disposed on two sides of the guiding portion <NUM>. Band plates extending along the second direction are formed on left and right sides of the guiding portion <NUM> and stand at right angles to the cover plate <NUM>. The band plates on the left and right sides of the guiding portion <NUM> form a space so as to adapt to the communication terminal portion <NUM> of the second bracket <NUM>. Specifically, the communication terminal portion <NUM> is slidably coupled to the first bracket <NUM> along the band plates on the left and right sides of the guiding portion <NUM>, and the guiding portion <NUM> can accommodate the communication terminal portion <NUM>. In some other embodiments, the positive terminal portion <NUM> and the negative terminal portion <NUM> of the first bracket <NUM> are disposed adjacent to each other, and the guiding portion <NUM> is disposed adjacent to the positive terminal portion <NUM> or the negative terminal portion <NUM>. Accordingly, a position where the communication terminal portion <NUM> of the second bracket <NUM> is disposed is adapted to the guiding portion <NUM> so that when the second bracket <NUM> is coupled to the first bracket <NUM>, the guiding portion <NUM> can fit with the communication terminal portion <NUM>.

In some embodiments, the first bracket <NUM> further includes a base <NUM>, where the base <NUM> is a component configured to fix the first bracket <NUM> to a predetermined position of the cover plate <NUM>. The base <NUM> is provided so that an accommodation space for accommodating part of the circuit board <NUM> is formed between the first bracket <NUM> and the cover plate <NUM>. In this manner, the overall structure of the first bracket <NUM>, the second bracket <NUM>, and the circuit board <NUM> is more compact, and a dimension of the battery pack is reduced. Moreover, the cover plate <NUM> is further provided with multiple limiting portions so as to provide convenience for guiding the second bracket <NUM> to be coupled to the first bracket <NUM> along the second direction. In this manner, the circuit board <NUM> is disposed more stably, and the anti-vibration performance of the battery pack is improved. Specifically, referring to <FIG>, the cover plate <NUM> is further provided with a first limiting portion <NUM>, a second limiting portion <NUM>, and a third limiting portion <NUM>. The first limiting portion <NUM> and the second limiting portion <NUM> are disposed on left and right sides of the circuit board <NUM> to assist the guiding portion <NUM> of the first bracket <NUM> in guiding the second bracket <NUM> to be coupled to the first bracket <NUM> along the second direction. At the same time, the first limiting portion <NUM> and the second limiting portion <NUM> assist the guiding portion <NUM> in guiding the sub circuit board <NUM> to be coupled to the accommodation space formed by the first bracket <NUM> and the cover plate <NUM> along the second direction so that after the second bracket <NUM> is coupled to the first bracket <NUM> and the circuit board <NUM> is coupled to the accommodation space between the first bracket <NUM> and the cover plate <NUM>, the circuit board <NUM> is disposed more stably and will not move left and right with the vibration of the battery pack. In some embodiments, the third limiting portion <NUM> is further provided on the cover plate <NUM> and on a lower side of the circuit board <NUM> so that after the second bracket <NUM> is coupled to the first bracket <NUM> and the circuit board <NUM> is coupled to the accommodation space between the first bracket <NUM> and the cover plate <NUM>, the circuit board <NUM> is disposed more stably and will not move up and down with the vibration of the battery pack.

Referring to <FIG> which is a schematic view of the second bracket <NUM> and the circuit board <NUM>, the second bracket <NUM> further includes multiple snap fits <NUM>. Specifically, multiple protrusions extend downward from the second bracket <NUM> to form the snap fits <NUM>, and multiple slots <NUM> corresponding to the snap fits <NUM> are provided on the circuit board <NUM>. Therefore, the snap fits <NUM> mate with the slots <NUM> so that the second bracket <NUM> is detachably connected to the circuit board <NUM>. In some embodiments, a height of the snap fit <NUM> is the same as a thickness of the circuit board <NUM>. In some other embodiments, the height of the snap fit <NUM> is greater than the thickness of the circuit board <NUM>. After the second bracket <NUM> is connected to the circuit board <NUM>, the snap fit <NUM> protrudes from a lower surface of the circuit board <NUM> and abuts against the cover plate <NUM>. In this manner, the snap fit <NUM> is equivalent to the third limiting portion <NUM> so that after the second bracket <NUM> is coupled to the first bracket <NUM> and the circuit board <NUM> is coupled to the accommodation space between the first bracket <NUM> and the cover plate <NUM>, the circuit board <NUM> is disposed more stably and will not move up and down with the vibration of the battery pack.

The battery pack further includes a detection sensor configured to detect operating parameters of the cell assembly <NUM> or the cell unit <NUM> and transmit the operating parameters to the circuit board <NUM>. One or more detection sensors may be provided. In some embodiments, the detection sensor may be a temperature sensor. The temperature sensor is disposed on a surface of the cell assembly <NUM> or a surface of the cell unit <NUM> and connected to the circuit board <NUM> to transmit temperature information of the cell assembly <NUM> to the circuit board <NUM>. In some embodiments, the detection sensor may be a voltage sensor configured to detect the voltage of the cell unit <NUM> and connected to the circuit board <NUM> to transmit temperature information of the cell assembly <NUM> to the circuit board <NUM>. In some embodiments, the battery pack includes the temperature sensor, the voltage sensor, and a detection circuit board <NUM>, and the temperature sensor and the voltage sensor are integrated on the detection circuit board <NUM>. To facilitate detection, the detection circuit board <NUM> is disposed on a side of the positive terminal of the cell assembly <NUM> and the negative terminal of the cell assembly <NUM>. At the same time, to save space and improve the reliability of the battery pack, the detection circuit board <NUM> may also be a flexible printed board (FPC) which may be bent. It is to be understood that the battery pack may further include other types of sensors so that the circuit board <NUM> can collect the information of the battery pack through various sensors and transmit the information of the battery pack through the communication terminal <NUM> of the battery pack to the power tool or the charger attached to the battery pack.

As shown in <FIG>, the battery pack <NUM> further includes a detection line output socket <NUM> connected to a sensor connection line <NUM>, where the sensor connection line <NUM> is electrically connected to the circuit board <NUM> through the detection line output socket <NUM>. The sensor connection line <NUM> is connected to the detection sensor on the detection circuit board <NUM> so as to output a sensor signal to the circuit board <NUM>. To facilitate the detachable connection of the circuit board <NUM> and the battery pack, the detection line output socket <NUM> is detachably connected to the circuit board <NUM> so that the sensor connection line <NUM> is detachably connected to the circuit board <NUM>. Therefore, in some embodiments, the detection line output socket <NUM> is detachably connected to the second bracket <NUM>. Specifically, the sensor connection line <NUM> is connected to the detection line output socket <NUM> by a wire harness, and the second bracket <NUM> is provided with a socket adapter structure so that the detection line output socket <NUM> is detachably connected to the second bracket <NUM>. In some other embodiments, multiple detection line output sockets <NUM> may be provided, and the second bracket <NUM> is provided with socket adapter structures whose number matches the number of the detection line output sockets <NUM>. In this embodiment, the battery pack includes a first detection line output socket and a second detection line output socket. The first detection line output socket and the second detection line output socket are disposed on two sides of a power display switch, and six sensor connection lines <NUM> are plugged into each of the first detection line output socket and the second detection line output socket. It is to be understood that one detection line output socket <NUM> may be provided, and different numbers of sensor connection lines <NUM> may be plugged into the detection line output socket <NUM>. The number of sensor connection lines <NUM> may be determined according to the number of detection sensors, which is not limited herein.

As shown in <FIG>, multiple sensor connection lines <NUM> are plugged into the detection line output socket <NUM>. Since the sensor connection lines are arranged relatively close, two adjacent sensor connection lines are easy to touch when being plugged or unplugged, causing a short circuit, thereby damaging the detection circuit board and even the cell. Therefore, a resistor is connected in series on each sensor connection line to limit a current when two adjacent sensor connection lines are short-circuited, thereby protecting the detection circuit board and the cell.

Referring to <FIG>, <FIG>, the battery pack further includes a connection piece <NUM>. Specifically, the battery pack <NUM> includes a positive electrode connection piece 19A and a negative electrode connection piece 19B. The positive electrode connection piece 19A is connected in series between the positive terminal <NUM> of the battery pack and the positive terminal <NUM> of the cell assembly, and the negative electrode connection piece 19B is connected in series between the negative terminal <NUM> of the battery pack and the negative terminal <NUM> of the cell assembly. In an embodiment, the negative electrode connection piece 19B is disposed on a lower side of the negative terminal <NUM> of the battery pack, and part of the negative electrode connection piece 19B is disposed between the circuit board <NUM> and the negative terminal <NUM> of the battery pack. Specifically, the negative electrode connection piece 19B is disposed in an accommodation space formed between the negative terminal <NUM> of the battery pack and the cover plate <NUM>. Similarly, the positive electrode connection piece 19A is disposed in an accommodation space formed between the positive terminal <NUM> of the battery pack and the cover plate <NUM>.

The battery pack <NUM> further includes a current sensor <NUM> disposed at a position of the circuit board <NUM> where the current sensor <NUM> is capable of sensing a current flowing through the positive electrode connection piece 19A or the negative electrode connection piece 19B so as to detect an input current or an output current of the battery pack. Generally, the current sensor <NUM> is disposed at a position where the current sensor <NUM> is capable of sensing a magnetic field of the positive electrode connection piece 19A or the negative electrode connection piece 19B and on a side of the circuit board <NUM> facing towards the positive electrode connection piece 19A or the negative electrode connection piece 19B. Specifically, the current sensor <NUM> is disposed on a lower side of the positive electrode connection piece 19A or the negative electrode connection piece 19B, and the current sensor <NUM> is spaced apart from the positive electrode connection piece 19A or the negative electrode connection piece 19B.

In some embodiments, referring to <FIG> which is a top view of a positional relationship between the current sensor <NUM> and the positive electrode connection piece 19A or the negative electrode connection piece 19B, the current sensor <NUM> is disposed close to an edge of the positive electrode connection piece 19A or the negative electrode connection piece 19B so that the current sensor <NUM> can sense the current flowing through the positive electrode connection piece 19A or the negative electrode connection piece 19B. A size and a shape of the circuit board where the current sensor <NUM> is located may be set according to a position of the current sensor <NUM>. Moreover, the battery pack may correspondingly include multiple circuit boards so that the current sensor <NUM> is disposed close to the edge of the positive electrode connection piece 19A or the negative electrode connection piece 19B.

In some other embodiments, referring to <FIG> which is a side view of the positional relationship between the current sensor <NUM> and the positive electrode connection piece 19A or the negative electrode connection piece 19B, the current sensor <NUM> is disposed close to an outer surface of the positive electrode connection piece 19A or the negative electrode connection piece 19B. Optionally, the current sensor <NUM> is close to a lower surface of the positive electrode connection piece 19A or the negative electrode connection piece 19B so that the current sensor <NUM> can sense the current flowing through the positive electrode connection piece 19A or the negative electrode connection piece 19B. Referring to <FIG>, in this embodiment, it is defined that the circuit board <NUM> is formed with a third region <NUM>, and a projection plane of the third region <NUM> in the up-and-down direction coincides with a projection plane of the positive electrode connection piece 19A and/or the negative electrode connection piece 19B in the up-and-down direction. The current sensor <NUM> is disposed in the second region <NUM> of the circuit board <NUM>. Optionally, the current sensor <NUM> is disposed in the third region <NUM> of the circuit board <NUM>. Optionally, the current sensor <NUM> is disposed at a position close to a center of the third region <NUM> in the third region <NUM> of the circuit board <NUM> so that the current sensor <NUM> receives more magnetic fields around the positive electrode connection piece 19A or the negative electrode connection piece 19B so as to more accurately sense the current flowing through the positive electrode connection piece 19A or the negative electrode connection piece 19B. In this embodiment, the positive electrode connection piece 19A includes a positive current detection portion <NUM>, and the negative electrode connection piece 19B includes a negative current detection portion <NUM>, where the positive current detection portion <NUM> and the negative current detection portion <NUM> are arranged in parallel with the circuit board <NUM>, and the current sensor <NUM> is disposed on a lower side of the positive current detection portion <NUM> or the negative current detection portion <NUM>.

The current sensor <NUM> is a chip-type current sensor and can perform current sampling in a non-contact manner so that the discharge current or the charge current of the battery pack <NUM> is directly outputted to the power tool through the positive terminal <NUM> of the battery pack and the negative terminal <NUM> of the battery pack without passing through the circuit board <NUM>. In this manner, a large amount of heat generated by the positive terminal <NUM> of the battery pack and the negative terminal <NUM> of the battery pack can be prevented from being conducted to the circuit board <NUM>, and the heat generation of the circuit board <NUM> is also reduced, thereby reducing the heat generation of the battery pack <NUM>, improving the safety of the circuit board <NUM>, and improving the reliability of the battery pack <NUM>. The positive electrode connection piece 19A and the negative electrode connection piece 19B are each made of a metal, and the current sensor <NUM> may be a Hall sensor.

The battery pack <NUM> further includes a cell support <NUM> configured to support the cell assembly <NUM>, and the cell support <NUM> is made of a second material that is different from the first material. In some embodiments, the second material is a thermosetting material, and the first material of the housing <NUM> is a thermoplastic material. Optionally, a hardness of the second material is different from a hardness of the first material. In some embodiments, the hardness of the second material is less than the hardness of the first material so that the housing with greater hardness can better protect the cell assembly <NUM>. The cell support <NUM> is at least disposed at two ends of the cell assembly <NUM>, and at least part of the cell support <NUM> encapsulates the positive electrode of the cell unit and the negative electrode of the cell unit. Therefore, the second material may be an insulating material which can insulate the positive electrode of the cell unit and the negative electrode of the cell unit encapsulated by the cell support <NUM> so as to prevent the leakage of electricity.

In some embodiments, the cell support <NUM> includes a first support and a second support. The first support is disposed on a front end surface of the cell assembly <NUM>, where the front end surface is a surface of the cell assembly <NUM> where the positive electrode of the cell unit <NUM> and the negative electrode of the cell unit are provided. The second support is disposed on a rear end surface of the cell assembly <NUM>, where the rear end surface and the front end surface are opposite to each other. Optionally, the cell support <NUM> covers and fixes the positive electrode of the cell unit, the negative electrode of the cell unit, the positive lead-out piece <NUM>, and the negative lead-out piece <NUM>. In this embodiment, referring to <FIG>, the cell support <NUM> extends from the front end surface and the rear end surface of the cell assembly <NUM> to a left side surface, a right side surface, and a lower surface of the cell assembly <NUM> and is disposed around the front end surface, the rear end surface, the left side surface, the right side surface, and the lower bottom surface of the cell assembly <NUM> to form an accommodation space with an upper opening and for accommodating the cell assembly <NUM>. Specifically, the cell assembly <NUM> is placed in a mold, the support is formed around the front end surface, the rear end surface, the left side surface, the right side surface, and the lower surface of the cell assembly <NUM> in a glue injection manner, and then the cell assembly <NUM> and the shaped cell support <NUM> are taken out as a whole.

In this manner, the cell support <NUM> is configured to support the cell assembly <NUM>, avoiding a possible relative displacement between cell units <NUM> due to a bump or a vibration, thereby preventing the cells from being squeezed or kinked. Therefore, the cell support <NUM> can improve the anti-fall and shock-absorbing performance of the battery pack, thereby improving the reliability of the battery pack.

In some embodiments, a buffer layer is provided between cell units <NUM> and made of the second material. The buffer layer is provided between adjacent cell units <NUM>. The buffer layer is provided between cell units <NUM>, which is conducive to improving the anti-fall and shock-absorbing performance of the battery pack, thereby improving the reliability of the battery pack.

The battery pack <NUM> in the present application is applicable to a power tool <NUM> and detachably installed to the power tool <NUM>. As shown in <FIG> and <FIG>, the power tool <NUM> is an impact wrench. Although this embodiment relates to the impact wrench, it is to be understood that the present application is not limited to the embodiments described herein and is applicable to other types of power tools. The power tool may be, for example, a garden tool such as a string trimmer, a pruner, a blower, or a chainsaw. The power tool may also be a torque output tool such as an electric drill or an electric hammer. The power tool may also be a sawing tool such as an electric circular saw, a jig saw, or a reciprocating saw. The power tool may also be a grinding tool such as an angle grinder or a sander.

The power tool <NUM> includes a tool body <NUM> and a tool interface <NUM> and a tool mating portion <NUM> that are disposed on the tool body <NUM>. The tool body <NUM> includes a motor <NUM>, an output shaft <NUM>, and an impact mechanism <NUM>. The output shaft <NUM> is driven by the motor <NUM>. The impact mechanism <NUM> connects the motor <NUM> to the output shaft <NUM>. The impact mechanism <NUM> is driven by the motor <NUM> and applies an impact to the output shaft <NUM>. The power tool <NUM> further includes a handle <NUM> that can be held by a user to operate the power tool. The handle <NUM> is further provided with a trigger switch <NUM>. The trigger switch <NUM> is configured to be driven by the user to start or stop the operation of the motor <NUM>. The tool interface <NUM> is configured to adapt to the battery pack interface <NUM> so that the battery pack <NUM> is connected and supplies power to the power tool <NUM>. Moreover, the tool mating portion <NUM> is detachably connected to the battery pack coupling portion <NUM>. In some embodiments, the tool mating portion <NUM> is disposed at a lower end of the handle <NUM> of the power tool and configured to be detachably connected to the battery pack <NUM>. Generally, the battery pack coupling portion <NUM> is provided with a pair of sliding portions each with an inverted L-shaped cross section. Correspondingly, the sliding portions can slide along the tool mating portion <NUM> at a bottom of the handle so that the sliding portions can be installed to the tool body <NUM> through the tool mating portion <NUM>, where the tool mating portion <NUM> may be provided as a pair of guide rails. Specifically, when the user slides the battery pack toward the front of the tool body <NUM>, the battery pack <NUM> may be connected to the tool body <NUM>.

Currently, battery packs for supplying power to power tools mostly use cylindrical lithium cells. Multiple cylindrical lithium cells connected in series and in parallel ensure sufficient electric power output so that the endurance of the power tools is improved. For example, an output voltage of a cylindrical lithium cell is about <NUM> V, and then the maximum number of lithium cells connected in series in a battery pack with an output voltage of <NUM> V is <NUM>.

However, with the development of battery technology, a battery pack with a higher output voltage and a relatively low impedance in a chemical composition and configuration form may have the problem of compatibility with a power tool in the related art. When the internal resistance of the battery pack is reduced, the battery pack can supply a substantially higher current to the power tool. When the current increases beyond the expectations or design limits of the motor and electronic elements of the power tool, the power tool may burn out or enter over-current protection and become unusable. To solve the defects in the related art, the present application provides a power tool system and a battery pack thereof which can improve the compatibility of the battery pack and expand the usage scenarios of the battery pack. A detailed description is given below.

<FIG> shows a power tool system <NUM>, where the power tool system <NUM> includes a power tool <NUM> and a first rechargeable battery pack <NUM> and a second rechargeable battery pack <NUM> that can adapt to the power tool to supply power to the power tool. In <FIG>, the power tool <NUM> is an impact wrench. Although this embodiment relates to the impact wrench, it is to be understood that the present application is not limited to the embodiments described herein and is applicable to other types of power tools, which include, but are not limited to, an electric drill, a sander, an angle grinder, an electric wrench, a motorized saw, and the like.

As shown in <FIG>, each battery pack includes a housing, a cell assembly, and a battery pack interface. With the second rechargeable battery pack <NUM> as an example, a cell assembly <NUM> is disposed in an accommodation cavity formed by a housing <NUM>, and a second battery pack interface <NUM> and a battery pack coupling portion <NUM> are formed on an upper surface of the housing <NUM>. The battery pack interface <NUM> includes a power supply positive interface, a power supply negative interface, and a power supply communication interface. The battery pack supplies power to the power tool through the power supply positive interface and the power supply negative interface and communicates with the power tool through the power supply communication interface.

In some embodiments, an energy density (energy/mass of the battery pack) of the cell assembly <NUM> of the second rechargeable battery pack <NUM> shown in <FIG> is in a value range of greater than <NUM> Wh/kg. Optionally, the energy density (energy/mass of the battery pack) of the cell assembly <NUM> is in a value range of greater than <NUM> Wh/kg. Optionally, the energy density (energy/mass of the battery pack) of the cell assembly <NUM> is in a value range from <NUM> Wh/kg to <NUM> Wh/kg. Optionally, the energy density (energy/mass of the battery pack) of the cell assembly <NUM> is in a value range from <NUM> Wh/kg to <NUM> Wh/kg. Optionally, the energy density (energy/mass of the battery pack) of the cell assembly <NUM> is in a value range from <NUM> Wh/kg to <NUM> Wh/kg. Optionally, the energy density (energy/mass of the battery pack) of the cell assembly <NUM> is in a value range from <NUM> Wh/kg to <NUM> Wh/kg.

The battery pack composed of the flat plate-like cell assembly <NUM> may be referred to as "the second rechargeable battery pack <NUM>" hereinafter, and the battery pack composed of a cylindrical cell assembly <NUM>' for the power tool is referred to as "the first rechargeable battery pack <NUM>" so as to distinguish the two battery packs. The first rechargeable battery pack <NUM> is shown in <FIG>.

The first rechargeable battery pack <NUM> has a first battery pack interface <NUM> adaptable to a tool interface <NUM> of the power tool <NUM>, and the second rechargeable battery pack <NUM> has the second battery pack interface <NUM> adaptable to the tool interface <NUM> of the power tool <NUM>. A shape of the first battery pack interface <NUM> is basically the same as a shape of the second battery pack interface <NUM>. Specifically, the first battery pack interface <NUM> and the second battery pack <NUM> are disposed on an upper surface of the first battery pack <NUM> and an upper surface of the second battery pack <NUM>, respectively, and each of the first battery pack interface <NUM> and the second battery pack interface <NUM> includes at least the power supply positive interface, the power supply negative interface, and the power supply communication interface.

Compared with the first rechargeable battery pack <NUM>, the second rechargeable battery pack <NUM> has a different electrical characteristic. In some embodiments, the first rechargeable battery pack <NUM> has a first electrical characteristic adapted to the power tool <NUM>, and the second rechargeable battery pack <NUM> has a second electrical characteristic. The second electrical characteristic includes at least one of the following electrical parameters: an internal resistance of the second rechargeable battery pack <NUM> or a discharge current or full battery endurance of the second rechargeable battery pack <NUM>. Specifically, compared with the first rechargeable battery pack <NUM>, the second rechargeable battery pack <NUM> can output a similar or higher output voltage and has a relatively low internal resistance. In this manner, no matter when being charged or discharged, the second rechargeable battery pack <NUM> has a relatively low voltage drop and heat accumulation and thus can withstand relatively high charge and discharge currents. Therefore, the second rechargeable battery pack <NUM> can provide a relatively high current and power to the power tool <NUM>.

In some embodiments, the second rechargeable battery pack <NUM> shown in <FIG> has a discharge capacity of at least <NUM> A. In the case where the second rechargeable battery pack <NUM> is discharged at a rate of <NUM> C, a temperature rise is less than <NUM>. Moreover, an internal resistance of the cell assembly <NUM> of the second rechargeable battery pack <NUM> is less than or equal to <NUM> mΩ. Optionally, the internal resistance of the cell assembly <NUM> of the second rechargeable battery pack <NUM> is less than or equal to <NUM> mΩ. Optionally, the internal resistance of the cell assembly <NUM> of the second rechargeable battery pack <NUM> is less than or equal to <NUM> mΩ.

In some embodiments, the second rechargeable battery pack <NUM> shown in <FIG> has a discharge current of greater than or equal to <NUM> A. Optionally, the second rechargeable battery pack <NUM> has a discharge current of greater than or equal to <NUM> A. In this manner, the power tool <NUM> adaptable to the first rechargeable battery pack <NUM> is a first power tool <NUM>, and the power tool <NUM> that can be powered by the second rechargeable battery pack <NUM> is referred to as a second power tool <NUM>. Therefore, the first power tool <NUM> is designed to operate with the first rechargeable battery pack <NUM> that outputs a low current and a low power, and the first power tool <NUM> has first output performance. On the contrary, compared with the first power tool <NUM> powered by the first rechargeable battery pack <NUM>, when operating with the second rechargeable battery pack <NUM> attached to the second power tool <NUM>, the second power tool <NUM> can operate at a larger current and power, and the second power tool <NUM> has second output performance different from the first output performance.

However, when the first power tool <NUM> is powered by the second rechargeable battery pack <NUM>, the first power tool <NUM> may be damaged due to an excessive output capacity of the second rechargeable battery pack <NUM>. At a given current, the second rechargeable battery pack <NUM> has a lower voltage drop in the battery cells than the first rechargeable battery pack <NUM>. For example, when the first rechargeable battery pack <NUM> with a rated voltage of <NUM> V has an output current of <NUM> C, the first rechargeable battery pack <NUM> may output an output voltage of <NUM> V when charged at <NUM>%, while the second rechargeable battery pack <NUM> outputs an output voltage of at least <NUM> V at the same discharge current of <NUM> C when charged at <NUM>%. For example, when the first rechargeable battery pack <NUM> and the second rechargeable battery pack <NUM> both have a capacity of <NUM> Ah and an output current of <NUM> A, an input power of the first power tool <NUM> powered by the first rechargeable battery pack <NUM> is about <NUM> W, and an input power of the second power tool <NUM> powered by the second rechargeable battery pack <NUM> is about <NUM> W. The high output power limits the usage scenarios of the second rechargeable battery pack <NUM>. To solve this problem, the following embodiments can expand the usage scenarios of the second rechargeable battery pack <NUM> so that the second rechargeable battery pack <NUM> can adapt to both the first power tool <NUM> and the second power tool <NUM>.

<FIG> is a block diagram showing modules of a first power tool system <NUM> and modules of a second power tool system <NUM>. <FIG> shows the following principle: the first power tool <NUM> can be powered by the first rechargeable battery pack <NUM> and can also be powered by the second rechargeable battery pack <NUM>. Similarly, the second power tool <NUM> can be powered by the second rechargeable battery pack <NUM> and can also be powered by the first rechargeable battery pack <NUM>. In other words, the second rechargeable battery pack <NUM> can adapt to both the second power tool <NUM> and the first power tool <NUM> so that the compatibility of the battery pack is improved, thereby expanding the usage scenarios of the battery pack.

<FIG> is a circuit block diagram of a power tool system as one of embodiments. The power tool system includes a power tool <NUM> and a rechargeable battery pack <NUM> (a first rechargeable battery pack <NUM> or a second rechargeable battery pack <NUM>).

The rechargeable battery pack <NUM> includes at least multiple cells connected in series. <FIG> shows a cell assembly <NUM> composed of four cells connected in series. The rechargeable battery pack <NUM> may have more than four cells. The rechargeable battery pack <NUM> further includes a power supply positive terminal <NUM>, a power supply negative terminal <NUM>, a power supply communication terminal <NUM>, a power supply identification module <NUM>, and a temperature sensor <NUM>.

The power supply positive terminal <NUM> and the power supply negative terminal <NUM> are configured for output of a discharge current or input of a charge current. The power supply communication terminal <NUM> is configured for communication with a power tool <NUM>. The power supply positive terminal <NUM> is disposed in a power supply positive interface, the power supply negative terminal <NUM> is disposed in a power supply negative interface, and the power supply communication terminal <NUM> is disposed in a power supply communication interface.

The temperature sensor <NUM> is configured to detect a temperature of the cell assembly <NUM>. In some embodiments, the temperature sensor <NUM> is connected to the power supply communication terminal <NUM>. Specifically, the temperature sensor <NUM> is disposed on a surface of a cell and configured to detect a temperature of the surface of the cell.

When the temperature of the surface of the cell is greater than or equal to a threshold, the temperature sensor <NUM> outputs an over-temperature signal to the power tool <NUM> so that the power tool <NUM> stops receiving electric power outputted by the rechargeable battery pack <NUM>, thereby preventing the rechargeable battery pack <NUM> from explosion due to overheating. The temperature sensor <NUM> may be a thermistor such as a thermistor of a negative temperature coefficient (NTC) or a thermistor of a positive temperature coefficient (PTC).

The power supply identification module <NUM> stores an identifier (ID) of the rechargeable battery pack and is configured to identify the first rechargeable battery pack <NUM> or the second rechargeable battery pack <NUM> when inserted into a charger or a power tool. The ID of the rechargeable battery pack includes, for example, a model, a version, a cell configuration, and a battery type such as a battery with cylindrical cells or a battery with flat cells. The ID of the rechargeable battery pack may be one or more communication codes and may also be an ID resistor, a light-emitting diode (LED) display configured to display identification data of the rechargeable battery pack, serial data sent when the rechargeable battery pack is connected to and sensed by the power tool or the charger, fields in a frame of data sent to the power tool/charger through the power supply communication interface, or the like.

Moreover, the power tool <NUM> includes at least a motor <NUM>, a switch circuit <NUM>, a tool control module <NUM>, a tool identification module <NUM>, a tool interface positive terminal <NUM>, a tool interface negative terminal <NUM>, and a tool interface communication terminal <NUM>. The tool interface positive terminal <NUM> and the tool interface negative terminal <NUM> are configured to access the discharge current outputted by the rechargeable battery pack <NUM>. The tool interface communication terminal <NUM> enables the power tool <NUM> to communicate with the rechargeable battery pack <NUM>. Specifically, the tool interface positive terminal <NUM> is disposed in a tool positive interface and can be detachably connected to the power supply positive terminal <NUM> of the rechargeable battery pack <NUM>; the tool interface negative terminal <NUM> is disposed in a tool negative interface and can be detachably connected to the power supply negative terminal <NUM> of the rechargeable battery pack <NUM>; and the tool interface communication terminal <NUM> is disposed in a tool communication interface and can be detachably connected to the power supply communication terminal <NUM> of the rechargeable battery pack <NUM>.

The switch circuit <NUM> is configured to drive the motor <NUM> and electrically connected to the tool control module <NUM>. The switch circuit <NUM> receives electric power from the rechargeable battery pack <NUM> and is driven by a switch signal outputted by the tool control module <NUM> to distribute the voltage of the rechargeable battery pack <NUM> to each phase winding on a stator of the motor <NUM> with a certain logical relationship so that the motor <NUM> starts and rotates continuously. Specifically, the switch circuit <NUM> includes multiple electronic switches. In some embodiments, the electronic switch includes a field-effect transistor (FET). In some other embodiments, the electronic switch includes an insulated-gate bipolar transistor (IGBT).

The tool identification module <NUM> is configured to identify one of the first rechargeable battery pack <NUM> or the second rechargeable battery pack <NUM> connected through the tool interface <NUM>. The tool identification module <NUM> is connected to the tool interface communication terminal <NUM>. Through the tool interface communication terminal <NUM>, the tool identification module <NUM> can communicate with the battery pack attached to the power tool and sense information of the battery pack. The information of the battery pack includes the model, the version, the cell configuration, and the battery type such as the battery with cylindrical cells or the battery with flat cells. Therefore, the tool identification module <NUM> can determine, according to the information of the battery pack, whether the first rechargeable battery pack <NUM> or the second rechargeable battery pack <NUM> is connected through the tool interface <NUM> and transmit an identification signal to the tool control module <NUM>. In some embodiments, the tool identification module <NUM> can also transmit a shutdown signal to the tool control module <NUM> after receiving the over-temperature signal of the rechargeable battery pack <NUM> so as to control the first power tool <NUM> to shut down, thereby protecting the safety of the battery pack and the power tool.

In some embodiments, the tool identification module <NUM> may include a sensor. Specifically, the sensor may be a magnetic sensor or an inductive pickup sensor to sense the information of the battery pack attached to the power tool. Whether the first rechargeable battery pack <NUM> or the second rechargeable battery pack <NUM> is attached to the power tool is identified through radio frequency communication and light sensing.

The tool control module <NUM> is connected to at least the tool interface <NUM> and configured to control output performance of the first power tool <NUM> according to the rechargeable battery pack <NUM> connected through the tool interface <NUM>. Specifically, the tool control module <NUM> is configured to control, according to the identification signal, the voltage or current applied to two ends of the motor so that the motor can operate normally. For example, when the first power tool <NUM> is powered by the first rechargeable battery pack <NUM>, the tool identification module <NUM> identifies that the first rechargeable battery pack <NUM> is connected through the tool interface <NUM> and transmits a first identification signal to the tool control module <NUM>, and then the tool control module <NUM> may completely load the output voltage and current of the first rechargeable battery pack <NUM> to the motor <NUM>; the tool identification module <NUM> identifies that the second rechargeable battery pack <NUM> is connected through the tool interface <NUM> and transmits the identification signal to the tool control module <NUM>, and then the tool control module <NUM> limits the electric loaded to the two ends of the motor <NUM> through the switch circuit <NUM> by transmitting a pulse-width modulation (PWM) signal to the switch circuit <NUM>. The PWM signal may quickly turn on and off the multiple electronic switches in the switch circuit <NUM> and distribute an average voltage across the motor, where the average voltage is lower than an input voltage of the rechargeable battery pack <NUM>. It is to be understood that the tool identification module <NUM> and the tool control module <NUM> may be integrated or may be provided separately.

<FIG> is a circuit block diagram of a power tool system as another embodiment. A difference from the power tool system shown in <FIG> is that the second power tool <NUM> shown in <FIG> further includes a power limiting module <NUM>.

The power limiting module <NUM> is configured to limit an input current from the rechargeable battery pack <NUM> to limit power input. The power limiting module <NUM> may increase a resistance value according to an identification signal received from a tool identification module <NUM>. The tool identification module <NUM> may sense the type of the rechargeable battery pack <NUM> (the first rechargeable battery pack <NUM> or the second rechargeable battery pack <NUM>) attached to the second power tool <NUM> and transmit the identification signal to a tool control module <NUM> so as to indicate whether the first rechargeable battery pack <NUM> or the second rechargeable battery pack <NUM> is attached, and the tool control module <NUM> transmits a control signal to the power limiting module <NUM> according to the identification signal. Therefore, the power limiting module <NUM> is configured to receive the control signal from the tool control module <NUM> so as to increase impedance to limit a maximum input current from the rechargeable battery pack <NUM> or to maintain the maximum input current from the rechargeable battery pack <NUM>.

In some embodiments, the power limiting module <NUM> is connected in series between a tool interface positive terminal <NUM> of the second power tool <NUM> and the motor. In some other embodiments, the power limiting module <NUM> is connected in series between a tool interface negative terminal <NUM> of the second power tool <NUM> and the motor. Specifically, the power limiting device <NUM> may be a passive resistor, and the power limiter <NUM> may also be an active resistor whose resistance changes with a load, for example, a semiconductor device or circuit with a current limiting function, such as the FET.

When the first rechargeable battery pack <NUM> supplies power to the second power tool <NUM>, the tool identification module <NUM> of the second power tool <NUM> transmits the identification signal to the tool control module <NUM> so as to indicate that the first rechargeable battery pack <NUM> is attached to the second power tool <NUM>, and then the tool control module <NUM> transmits the control signal to the power limiting module <NUM> according to the identification signal so that an output current of the power limiting module <NUM> remains a discharge current from the first rechargeable battery pack <NUM>. When the second rechargeable battery pack <NUM> supplies power to the second power tool <NUM>, the tool identification module <NUM> identifies, through a tool interface communication terminal <NUM>, that the second rechargeable battery pack <NUM> is connected and transmits the identification signal to the tool control module <NUM> so as to indicate that the second rechargeable battery pack <NUM> is attached to the second power tool <NUM>, and then the tool control module <NUM> transmits the control signal to the power limiting module <NUM> according to the identification signal so that the output current of the power limiting module <NUM> remains the maximum input current from the second rechargeable battery pack <NUM>, and thus the second power tool <NUM> operates at a larger current and power.

<FIG> is a circuit block diagram of a power tool system as another embodiment. A difference from the power tool system shown in <FIG> is that a rechargeable battery pack <NUM> further includes a power limiting module <NUM>.

In this embodiment, the power limiting module <NUM> is disposed in the rechargeable battery pack <NUM> and connected to a power supply communication terminal <NUM>. The power limiting module <NUM> is configured to limit an output current of the rechargeable battery pack <NUM> to limit power output. The power limiting module <NUM> may increase a resistance value according to the control signal received from the tool control module <NUM>. The tool identification module <NUM> may sense the type of the rechargeable battery pack <NUM> (the first rechargeable battery pack <NUM> or the second rechargeable battery pack <NUM>) attached to the first power tool <NUM> and transmit the identification signal to the tool control module <NUM> so as to indicate whether the first rechargeable battery pack <NUM> or the second rechargeable battery pack <NUM> is attached, and the tool control module <NUM> transmits the control signal to the power limiting module <NUM> according to the identification signal. Therefore, the power limiting module <NUM> is configured to receive the identification signal from the tool control module <NUM> so as to increase impedance to limit a maximum output current from the rechargeable battery pack <NUM> or to maintain the maximum input current of the rechargeable battery pack <NUM>. Specifically, the tool control module <NUM> transmits the control signal to the power limiting module <NUM> through the tool interface communication terminal <NUM> and the power supply communication terminal <NUM>.

The power limiting module <NUM> is disposed on a discharge path of the rechargeable battery pack <NUM>. In some embodiments, the power limiting module <NUM> is disposed between a negative electrode of the cell assembly and a power supply negative terminal <NUM>, and the power limiting module <NUM> may also be disposed between a positive electrode of the cell assembly and a power supply positive terminal <NUM>. Specifically, the power limiting module <NUM> may be a passive resistor that can effectively increase the internal resistance of the battery pack. The power limiting module <NUM> may also be an active resistor so that an internal resistance of the rechargeable battery pack <NUM> may change with the load. For example, the power limiting module <NUM> may be a semiconductor device or circuit with a current limiting function, such as the FET.

In some embodiments, when the power tool <NUM> is powered by the first rechargeable battery pack <NUM>, that is, when the first rechargeable battery pack <NUM> is connected through the tool interface <NUM>, the tool identification module of the power tool <NUM> transmits the identification signal to the tool control module so as to indicate that the first rechargeable battery pack <NUM> is attached to the power tool <NUM>, and then the tool control module transmits the control signal to the power limiting module in the first rechargeable battery pack <NUM> so that the power limiting module keeps the first rechargeable battery pack <NUM> to discharge at a maximum discharge current, that is, a first discharge current. When the second rechargeable battery pack <NUM> is used as a power supply of the power tool, if the power tool is the first power tool <NUM>, the tool identification module <NUM> identifies, through a tool communication terminal <NUM>, that the second rechargeable battery pack <NUM> is connected and transmits the identification signal to the tool control module <NUM> so as to indicate that the second rechargeable battery pack <NUM> is attached to the first power tool <NUM>, and then the tool control module <NUM> transmits a second control signal to the power limiting module so that the power limiting module increases impedance to limit the maximum output current of the rechargeable battery pack, that is, a second discharge current, where the second discharge current is less than or equal to the first discharge current so that the power tool is prevented from burning out or entering the over-current protection and failing to start. In some embodiments, when the tool identification module identifies, through the tool communication terminal, that the second rechargeable battery pack <NUM> is connected through the tool interface, the tool identification module transmits the second control signal to the control module so as to control the second rechargeable battery pack <NUM> to discharge at the second discharge current which is not greater than the first discharge current. When the second rechargeable battery pack <NUM> is used as the power supply of the power tool, if the power tool is the second power tool <NUM>, the tool identification module identifies, through the tool communication terminal, that the second rechargeable battery pack <NUM> is connected through the tool interface and transmits the identification signal to the control module so as to indicate that the second rechargeable battery pack <NUM> is attached to the second power tool <NUM>, and then the control module transmits a first control signal to the power limiting module so that the power limiting module maintains the maximum output current of the rechargeable battery pack, and thus the power tool operates at a larger current and power.

<FIG> is a circuit block diagram of a power tool system as another embodiment. A difference from the power tool system shown in <FIG> is that a rechargeable battery pack <NUM> further includes a power supply control module <NUM> and a power limiting module <NUM>. In this embodiment, the power supply control module <NUM> and the power limiting module <NUM> are disposed in the rechargeable battery pack. A temperature sensor <NUM> is configured to detect a temperature of a cell assembly and communicatively connected to the power supply control module <NUM>. Specifically, the temperature sensor <NUM> is configured to detect a temperature of a cell. When the temperature of the cell is greater than or equal to a threshold, the temperature sensor <NUM> outputs an over-temperature signal to the power supply control module <NUM> to cause the battery pack <NUM> to stop outputting electric power, thereby preventing the battery pack from explosion due to overheating. The temperature sensor may be a thermistor such as a thermistor of an NTC or a thermistor of a PTC. Since such a temperature sensor <NUM> is well-known in the art, the detailed description of functional operations is omitted for brevity.

A power supply identification module <NUM> is configured to identify a power tool connected through a power supply interface. Optionally, the power supply identification module <NUM> is configured to identify that the power tool connected through the battery pack interface is one of the first power tool <NUM> or the second power tool <NUM>. The power supply identification module <NUM> is connected to a power supply communication terminal <NUM>. The power supply identification module <NUM> communicates with the power tool attached to the battery pack and senses information of the power tool through the power supply communication terminal <NUM>. The information of the power tool includes one or more of a power limit, a current limit, or a voltage limit of the power tool. Therefore, the power supply identification module <NUM> can determine, according to the information of the power tool, whether the first power tool <NUM> or the second power tool <NUM> is connected through the power supply interface and transmit an identification signal to the power supply control module <NUM>. Specifically, if the rechargeable battery pack in operation is connected to the first power tool <NUM>, the power supply identification module <NUM> receives a signal including information of the first power tool <NUM> via the power supply communication terminal <NUM>. If the rechargeable battery pack in operation is connected to the second power tool <NUM>, the power supply identification module <NUM> receives a signal including information of the second power tool <NUM> via the power supply communication terminal <NUM>.

The power supply control module <NUM> controls a maximum power and a maximum current outputted by the rechargeable battery pack. The power supply control module <NUM> is communicatively connected to the power limiting module <NUM>. The power supply control module <NUM> is configured to receive the identification signal from the power supply identification module <NUM> and according to the identification signal from the identification module, adjust impedance of the power limiting module <NUM> so as to limit the maximum power and the maximum current of the rechargeable battery pack or maintain a relatively low internal resistance of the power limiting module <NUM> to maintain the maximum power and the maximum current of the rechargeable battery pack. The power supply control module <NUM> may be a digital controller, a microprocessor, an analog circuit, a digital signal processor, or one or more digital integrated circuit (IC) smart devices of an application-specific integrated circuit (ASIC).

In some embodiments, when the second rechargeable battery pack <NUM> is connected to the first power tool <NUM>, the power supply identification module receives the signal including the information of the first power tool <NUM> and transmits the signal to a discharge control module, and the discharge control module adjusts the impedance of the power limiting module so as to control the second rechargeable battery pack <NUM> to discharge at the second discharge current which is not greater than the first discharge current. When the second rechargeable battery pack <NUM> is connected to the second power tool <NUM>, the power supply identification module receives the signal including the information of the second power tool <NUM> and transmits the signal to a second discharge control module, and the second discharge control module adjusts the impedance of the power limiting module to a minimum value so that the second rechargeable battery pack <NUM> is discharged at a third discharge current greater than the first discharge current.

Moreover, when the second rechargeable battery pack <NUM> is connected to the second power tool <NUM>, the discharge control module controls the second rechargeable battery pack <NUM> to supply electric power to the second power tool at a second voltage, where the second voltage is greater than a first voltage. Specifically, when the second rechargeable battery pack <NUM> is connected through the tool interface of the second power tool <NUM>, the power supply identification module receives the signal including the information of the second power tool <NUM> and transmits the signal to the second discharge control module, and the second discharge control module adjusts the impedance of the power limiting module to the minimum value so that the second rechargeable battery pack <NUM> outputs electric power at the second voltage.

Referring to <FIG> which is a circuit block diagram of a power tool system as another embodiment, a power tool <NUM> further includes a connection unit <NUM>, a first discharge module <NUM>, and a second discharge module <NUM>.

The first discharge module <NUM> and the second discharge module <NUM> include other electronic elements in the power tool, and the first discharge module <NUM> and the second discharge module <NUM> have at least one or more of different power limits, current limits, or voltage limits. In some embodiments, the first discharge module <NUM> is adaptable to the first rechargeable battery pack <NUM>. When the first battery pack is used as a power source of the power tool, the first discharge module operates so that the first power tool has first output performance. The second discharge module <NUM> is adaptable to the second rechargeable battery pack <NUM>. When the second battery pack is used as the power source of the power tool, the second discharge module operates so that the power tool has second output performance different from the first output performance.

The connection unit <NUM> is selectively connected to the first discharge module <NUM> and the second discharge module <NUM>. The connection unit <NUM> has an input terminal, an output terminal, and a control terminal. The input terminal of the connection unit <NUM> is connected to a tool positive terminal <NUM>, the output terminal of the connection unit <NUM> is selectively connected to the first discharge module <NUM> or the second discharge module <NUM>, and the control terminal of the connection unit <NUM> is connected to a control module <NUM>. In some embodiments, when the first rechargeable battery pack <NUM> is connected through the tool interface, the connection unit <NUM> is connected to the first discharge module <NUM>; and when the second rechargeable battery pack <NUM> is connected through the tool interface, the connection unit <NUM> is connected to the second discharge module <NUM>. It is to be understood that the connection unit <NUM>, the first discharge module <NUM>, and the second discharge module <NUM> may also be connected in series between a tool negative terminal <NUM> and the motor.

A tool identification module <NUM> may sense the type of the rechargeable battery pack (the first rechargeable battery pack <NUM> or the second rechargeable battery pack <NUM>) attached to the power tool and directly transmit the sensed signal to the control module <NUM> so as to indicate whether the first rechargeable battery pack <NUM> or the second rechargeable battery pack <NUM> is attached. Therefore, the control module <NUM> is configured to control, according to the identification signal, the connection unit <NUM> to be selectively connected to the first discharge module <NUM> and the second discharge module <NUM>. Specifically, the control module <NUM> is configured to: when the first rechargeable battery pack <NUM> is connected through the tool interface, control the connection unit <NUM> to connect the tool positive terminal to the first discharge module <NUM>, and when the second rechargeable battery pack <NUM> is connected through the tool interface, control the connection unit <NUM> to connect the tool positive terminal to the second discharge module <NUM>.

The battery packs for supplying power to the power tools mostly use cylindrical lithium cells. Multiple cylindrical lithium cells connected in series and in parallel ensure sufficient electric power output so that the endurance of the power tools is improved. For example, an output voltage of a cylindrical lithium cell is about <NUM> V, and then the maximum number of lithium cells connected in series in a battery pack with an output voltage of <NUM> V is <NUM>.

With the development of battery technology, a battery pack with a higher output voltage and a relatively low impedance in a chemical composition and configuration form and various other different battery packs bring inconvenience to the user since a specific charger needs to be specially designed for each battery pack to charge the battery pack. To solve the defects in the related art, an object of the present application is to provide a charging system and a battery pack which can improve the charging compatibility of the charging system and the battery pack. A detailed description is given below.

<FIG> and <FIG> show a charging system <NUM>, where the charging system includes a first rechargeable battery pack <NUM>, a second rechargeable battery pack <NUM>, and a charger <NUM> that is adaptable to the first rechargeable battery pack <NUM> and the second rechargeable battery pack <NUM> to charge the battery pack.

<FIG> shows a circuit block diagram of a charging system <NUM> according to an embodiment. The charging system <NUM> includes a rechargeable battery pack (the first rechargeable battery pack <NUM> or the second rechargeable battery pack <NUM>) and a charger (a first charger <NUM> or a second charger <NUM>). Since the first rechargeable battery pack <NUM> and the second rechargeable battery pack <NUM> have the same circuit block diagram and the first charger <NUM> and the second charger <NUM> have the same circuit block diagram, the circuit block diagrams of the first rechargeable battery pack <NUM> and the first charger <NUM> are used as an example.

The first rechargeable battery pack <NUM> includes at least multiple cells connected in series. <FIG> shows four cells connected in series. The rechargeable battery pack may have more than four cells, and the number of cells is not limited herein. The rechargeable battery pack further includes a power supply positive terminal <NUM>, a power supply negative terminal <NUM>, a power supply communication terminal <NUM>, a power supply identification module <NUM>, and a temperature sensor <NUM>.

The power supply positive terminal <NUM> and the power supply negative terminal <NUM> are configured for output of a discharge current or input of a charge current. The power supply communication terminal <NUM> is configured for communication with the charger. The power supply positive terminal <NUM> is disposed in a power supply positive interface, the power supply negative terminal <NUM> is disposed in a power supply negative interface, and the power supply communication terminal <NUM> is disposed in a power supply communication interface.

The temperature sensor <NUM> is configured to detect a temperature of a cell assembly. In some embodiments, the temperature sensor <NUM> is connected to the power supply communication terminal <NUM>. Specifically, the temperature sensor <NUM> is disposed on a surface of a cell and configured to detect a temperature of the surface of the cell. The temperature sensor <NUM> may be a thermistor such as a thermistor of an NTC or a thermistor of a PTC.

The power supply identification module <NUM> stores an ID of the rechargeable battery pack and is configured to identify the first rechargeable battery pack <NUM> or the second rechargeable battery pack <NUM> when inserted into the charger. The ID of the rechargeable battery pack includes, for example, a model, a version, a cell configuration, and a battery type such as a battery with cylindrical cells or a battery with flat cells. The ID of the rechargeable battery pack may be one or more communication codes and may also be an ID resistor, an LED display configured to display identification data of the rechargeable battery pack, serial data sent when the rechargeable battery pack is connected to or sensed by a power tool or the charger, fields in a frame of data sent to the charger through the power supply communication interface, or the like.

The first charger <NUM> includes a current detection module <NUM>, a power detection module <NUM>, a temperature detection module <NUM>, a charging identification module <NUM>, a charging control module <NUM>, and a current control module <NUM>. Moreover, the charger <NUM> further includes a switch module <NUM> configured to allow and prevent a charge current and a power supply module <NUM> configured to adjust an external power supply to electric power that may be used by other electronic components or circuits in the battery pack and the charger. Of course, the power detection module <NUM> and the temperature detection module <NUM> may also be disposed in the battery pack, which is not limited herein.

The current detection module <NUM> is configured to detect the charge current of the charger <NUM>. In some embodiments, the current detection module <NUM> is a resistor and detects a voltage applied to the resistor so as to obtain the charge current flowing into the battery pack.

The power supply module <NUM> includes a rectifier circuit and a filter circuit and is configured to rectify and filter an alternating current from an alternating current power supply to output a direct current.

The charger <NUM> further includes an output positive terminal <NUM>, an output negative terminal <NUM>, and a charging communication terminal <NUM>. The output positive terminal <NUM> and the output negative terminal <NUM> are configured for output of the charge current. The charging communication terminal <NUM> is configured for communication with the first rechargeable battery pack <NUM>.

When the first rechargeable battery pack <NUM> is inserted into the charger <NUM>, the temperature sensor <NUM> is coupled to the temperature detection module <NUM> of the charger, and the power detection module <NUM> is electrically connected to the power supply positive terminal <NUM> and the power supply negative terminal <NUM> at two ends of the battery pack and configured to detect the power of the battery pack <NUM>.

The charging identification module <NUM> is configured to identify one of the first rechargeable battery pack <NUM> or the second rechargeable battery pack <NUM> connected to the charger. The charging identification module <NUM> is connected to the charging communication terminal <NUM>. The charging identification module <NUM> can communicate with the battery pack attached to the charger and sense information of the battery pack through the charging communication terminal <NUM> to identify one of the first rechargeable battery pack <NUM> or the second rechargeable battery pack <NUM> connected to the charger and then transmit an identification signal to the charging control module <NUM>. The information of the battery pack includes the model, the version, the cell configuration, and the battery type such as the battery with cylindrical cells or the battery with flat cells. In some embodiments, the charging identification module <NUM> is a determination resistor that divides a reference voltage together with the power supply identification module. A voltage component is outputted as the information of the battery pack.

The charging control module <NUM> can determine, according to the information of the battery pack, whether the first rechargeable battery pack <NUM> or the second rechargeable battery pack <NUM> is connected through a charging interface so as to control the charge current of the charger. The charging control module <NUM> transmits a current control signal to the current control module <NUM> according to the identification signal. In this embodiment, in the case where the charger is connected to the first rechargeable battery pack <NUM>, the charging control module <NUM> controls the charger to charge the first rechargeable battery pack <NUM> at a first charge current; and in the case where the charger is connected to the second rechargeable battery pack <NUM>, the charging control module <NUM> controls the charger to perform charging at a second charge current.

The current control module <NUM> is configured to adjust the charge current flowing into the battery pack and communicatively connected to the charging control module <NUM>.

Therefore, the current control module <NUM> is configured to receive the current control signal from the charging control module <NUM> to limit a maximum output current from the power supply module or maintain the maximum output current of the power supply module. Specifically, the current control module <NUM> includes a power limiting device, where the power limiting device may be a passive resistor and may also be an active resistor whose resistance changes with the current control signal, for example, a semiconductor device or circuit with a current limiting function, such as the FET.

The switch module <NUM> is connected on a charging loop and coupled to the charging control module <NUM>. The switch module <NUM> receives a control signal from the charging control module <NUM> and switches a state of a switch to control the charging loop to be on or off.

The specific operation process is described below. The charging identification module <NUM> communicates with the battery pack attached to the charger and senses the information of the battery pack through the charging communication terminal <NUM> to identify one of the first rechargeable battery pack <NUM> or the second rechargeable battery pack <NUM> connected to the charger and transmits the identification signal to the charging control module <NUM>. At the same time, the power detection module <NUM> and the temperature detection module <NUM> also transmit the received power information and temperature information of the temperature sensor <NUM> to the charging control module <NUM>. After internally processing the information of the battery pack, the power information, and the temperature information, the charging control module <NUM> transmits the current control signal to the current control module <NUM> to adjust the charge current or the charging control module <NUM> transmits the current control signal to the switch module <NUM> to control the charging loop to be on or off so as to allow the charge current to flow into the battery pack or prevent the charge current from flowing into the battery pack. In this embodiment, a resistance of the current control module <NUM> is changed so as to change a charge current mode. If the resistance of the current control module <NUM> changes, at least two optional charge current modes are provided: a first charge current mode adaptable to the first rechargeable battery pack <NUM> and providing a relatively low current and a second charge current mode providing a charge current greater than the current in the first charge current mode, where the charge current in the first charge mode is the first charge current; and the charge current in the second charge mode is the second charge current.

<FIG> is a circuit block diagram of a charging combination <NUM> as another embodiment. A difference from the charging combination <NUM> shown in <FIG> is that the current control module is disposed in the rechargeable battery pack, that is, the first rechargeable battery pack <NUM> further includes a current control module <NUM>, where the current control module <NUM> is connected to the power supply communication terminal <NUM>.

The charging identification module <NUM> is configured to identify one of the first rechargeable battery pack <NUM> or the second rechargeable battery pack <NUM> connected to the charger. The charging identification module <NUM> is connected to the charging communication terminal <NUM>. The charging identification module <NUM> can communicate with the battery pack attached to the charger and sense the information of the battery pack through the charging communication terminal <NUM> to identify one of the first rechargeable battery pack <NUM> or the second rechargeable battery pack <NUM> connected to the charger and then transmit the identification signal to the charging control module <NUM>. The information of the battery pack includes the model, the version, the cell configuration, and the battery type such as the battery with cylindrical cells or the battery with flat cells. In some embodiments, the charging identification module is the determination resistor that divides the reference voltage together with the power supply identification module. The voltage component is outputted as the information of the battery pack.

The charging control module <NUM> can determine, according to the information of the battery pack, whether the first rechargeable battery pack <NUM> or the second rechargeable battery pack <NUM> is connected through a tool interface so as to control the charge current of the charger. The charging control module <NUM> transmits the current control signal to the current control module <NUM> according to the identification signal. In this embodiment, in the case where the charger is connected to the first rechargeable battery pack <NUM>, the charging control module <NUM> controls the charger to charge the first rechargeable battery pack <NUM> at the first charge current; and in the case where the charger is connected to the second rechargeable battery pack <NUM>, the charging control module controls the charger to charge the second rechargeable battery pack <NUM> at the second charge current or the first charge current.

The current control module <NUM> is configured to adjust a charge current flowing into the cell assembly. The current control module <NUM> receives the current control signal from the charging control module <NUM> through the power supply communication terminal <NUM> to adjust the charge current flowing into the cell assembly. Specifically, the current control module includes the power limiting device, where the power limiting device may be the passive resistor and may also be the active resistor whose resistance changes with the current control signal, for example, the semiconductor device or circuit with the current limiting function, such as the FET. In this embodiment, in the case where the charger is connected to the first rechargeable battery pack <NUM>, the current control module <NUM> controls the cell assembly to be charged at the first charge current; and in the case where the charger is connected to the second rechargeable battery pack <NUM>, the charging control module <NUM> controls the cell assembly to be charged at the second charge current. Therefore, the current control module is configured to receive the current control signal from the charging control module <NUM> so as to limit the maximum charge current from the charger or maintain the maximum charge current from the charger.

The specific operation process is described below. The charging identification module <NUM> communicates with the battery pack attached to the charger and senses the information of the battery pack through the charging communication terminal <NUM> to identify one of the first rechargeable battery pack <NUM> or the second rechargeable battery pack <NUM> connected to the charger and transmits the identification signal to the charging control module. At the same time, the power detection module <NUM> and the temperature detection module <NUM> also transmit the received power information and the temperature information of the temperature sensor to the charging control module <NUM>. After internally processing the information of the battery pack, the power information, and the temperature information, the charging control module <NUM> transmits the current control signal to the current control module <NUM> to adjust the charge current or the charging control module <NUM> transmits the current control signal to the switch module <NUM> to control the charging loop to be on or off so as to allow the charge current to flow into the battery pack or prevent the charge current from flowing into the battery pack. In this embodiment, the resistance of the current control module is changed so as to change the charge current mode. If the resistance of the current control module changes, at least two optional charge current modes are provided: the first charge current mode adaptable to the first rechargeable battery pack <NUM> and providing a relatively low current and the second charge current mode providing the charge current greater than the current in the first charge current mode, where the charge current in the first charge mode is the first charge current; and the charge current in the second charge mode is the second charge current.

<FIG> is a circuit block diagram of a charging combination <NUM> as another embodiment. A difference from the charging combination <NUM> shown in <FIG> is that a charging control module <NUM> is disposed in the rechargeable battery pack, that is, the rechargeable battery pack includes the charging control module <NUM>, where the charging control module <NUM> can control the switch module <NUM> to be on or off through the communication terminal <NUM>.

The power supply identification module <NUM> is configured to identify one of the first charger <NUM> or the second charger <NUM> connected to the rechargeable battery pack. The power supply identification module <NUM> is connected to the power supply communication terminal <NUM>. The power supply identification module <NUM> can communicate with the charger attached to the battery pack and sense information of the charger through the power supply communication terminal <NUM> to identify one of the first charger <NUM> or the second charger <NUM> connected to the rechargeable battery pack and then transmit the identification signal to the charging control module <NUM>. The information of the charger includes a charge voltage and a charge current.

The charging control module <NUM> can determine, according to the information of the battery pack, whether the first charger <NUM> or the second charger <NUM> is connected through a power supply interface so as to control the charge current of the cell assembly. The charging control module <NUM> transmits the current control signal to the current control module according to the identification signal.

The current control module <NUM> is configured to adjust the charge current flowing into the cell assembly. The current control module <NUM> receives the current control signal from the charging control module <NUM> through the power supply communication terminal <NUM> to adjust the charge current flowing into the cell assembly. Specifically, the current control module <NUM> includes the power limiting device, where the power limiting device may be the passive resistor and may also be the active resistor whose resistance changes with the current control signal, for example, the semiconductor device or circuit with the current limiting function, such as the FET.

In this manner, when the first rechargeable battery pack <NUM> is connected to the first charger <NUM>, the first charger <NUM> performs charging at the first charge current. Specifically, when the first rechargeable battery pack <NUM> is powered by the first charger <NUM>, the power supply identification module <NUM> of the first rechargeable battery pack <NUM> transmits the identification signal to the charging control module <NUM> to indicate that the first charger <NUM> is attached to the first rechargeable battery pack <NUM>, and the charging control module <NUM> transmits a first current control signal to the current control module <NUM> so that the current outputted from the current control module <NUM> to the cell assembly remains the first charge current from the first charger <NUM>. When the first rechargeable battery pack <NUM> is connected to the second charger <NUM>, the power supply identification module <NUM> identifies that the second charger <NUM> is connected and transmits the identification signal to the charging control module <NUM> to indicate that the second charger <NUM> is attached to the first rechargeable battery pack <NUM>, and the charging control module <NUM> transmits a second current control signal to the current control module <NUM> so that the current control module <NUM> limits the charge current from the second charger <NUM>, and thus the current outputted from the current control module <NUM> to the cell assembly is not greater than the first charge current, thereby preventing the first rechargeable battery pack <NUM> from being overcharged and damaged.

Claim 1:
A battery pack (<NUM>), comprising:
a housing (<NUM>) comprising an upper housing (<NUM>) and a lower housing (<NUM>) assembled at a boundary surface to form an inner cavity;
a cell assembly (<NUM>) disposed in the inner cavity;
a battery pack interface (<NUM>) electrically connected to at least the cell assembly; and
a circuit board (<NUM>) electrically connected to at least the cell assembly and the battery pack interface;
wherein the cell assembly comprises:
a plurality of cell units (<NUM>);
a positive terminal (<NUM>) of the cell assembly connected to at least a positive electrode of one of the plurality of cell units; and
a negative terminal (<NUM>) of the cell assembly connected to at least a negative electrode of one of the plurality of cell units;
wherein the battery pack interface comprises:
a positive terminal (<NUM>) of the battery pack connected to the positive terminal of the cell assembly;
a negative terminal (<NUM>) of the battery pack connected to the negative terminal of the cell assembly; and
a communication terminal (<NUM>) of the battery pack;
a first bracket (<NUM>) disposed on an upper side of the lower housing and configured to fix the positive terminal of the battery pack and the negative terminal of the battery pack; and
a second bracket (<NUM>) disposed on an upper side of the circuit board and connected to the circuit board, wherein the second bracket is detachably connected to the first bracket.