Patent Description:
When charging and discharging a battery pack for a car, a voltage difference between cells naturally occurs, and if it is used continuously in this state, some batteries may become overcharged and there is a risk of fire and some batteries are in an over-discharged state, causing problems such as shortening the lifetime of the battery pack.

In order to prevent this, a current is applied to a resistor connected to the cells of the battery pack to consume the voltage of each cell as heat, thereby performing balancing among the cells. While consuming the voltage of the cell in a limited space as heat, the resistor causes a rapid temperature rise, and to prevent this, the temperature is controlled by reducing the current, however, since this affects the cell balancing time, it is necessary to optimize the design by improving the position, arrangement, and driving method without reducing the current.

A cell ballancing module according to the preamble of claim <NUM> is disclosed in <CIT>.

<NPL> discloses a balancing module, which is divided in two boards. A local master, which has a local master microcontroller with all necessary connections for communication, and a power board with a bq76, MOSFETs and balancing resistors.

The technical problem to be solved by the present invention is to provide a cell balancing module for mounting a cell balancing resistor using a stack structure and a method for manufacturing the cell balancing module.

The problems of the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

In a first aspect, the present invention is directed to a cell balancing module comprising.

In addition, the sub-board may have the plurality of cell balancing resistors being formed on a surface facing or opposite to the main substrate.

In addition, the plurality of cell balancing resistors may consume a voltage of each battery cell by connecting two cell balancing resistors in series for each battery cell.

In addition, the sub-board the sub-board has a heat dissipation unit being formed on a surface not being mounted with the plurality of cell balancing resistors thereon.

In addition, it may include a control unit being mounted on the main substrate to control the connection of the plurality of cell balancing resistors.

In addition, the sub-boards may be plural, and connectors may be formed between the sub-boards adjacent to each other so that the adjacent sub-boards may be formed to be spaced apart from each other by a predetermined interval.

In addition, the connector may connect the main board and the sub-board through a connection line patterned therein.

In addition, at least one of an interval between cell balancing resistors, the number of cell balancing resistors, and the number of sub-boards may vary depending on heat density, balancing time, number of cells performing balancing, or space of cell balancing module.

In a second aspect, the present invention is directed to a a method for manufacturing a cell balancing module comprising the steps of: mounting a plurality of second cell balancing resistors on one or more sub-boards, and connecting a connector to form a resistor module; mounting a plurality of first cell balancing resistors and a control unit for controlling the first and second cell balancing resistors on a main board; and.

According to embodiments of the present invention, a larger number of resistors can be mounted using a stack structure, so that a plurality of cells can be balanced, and the time for cell balancing can be shortened. In addition, various resistors are available and the size of the cell balancing module can be reduced, thereby enabling compact and slim design. In addition, the heat density is reduced, which can reduce the temperature of the resistors and the module.

The effect according to the invention is not limited by the contents exemplified above, and more various effects are included in the present specification.

Hereinafter, particular arrangements will be described in detail with reference to the accompanying drawings.

However, the technical idea of the present invention is not limited to said arrangements, but may be implemented in various forms, said various forms being part of the present invention if they do not contradict the claims (i.e. if they comprise all features of at least one of the appended independent claims).

In addition, the terms (including technical and scientific terms) used herein, unless explicitly defined and described, can be interpreted as a meaning that can be generally understood by a person skilled in the art, and commonly used terms such as terms defined in the dictionary may be interpreted in consideration of the meaning of the context of the related technology.

In the present specification, the singular form may include the plural form unless specifically stated in the phrase, and when described as "at least one (or more than one) of A and B and C", it may include one or more of all combinations that can be combined with A, B, and C.

In addition, in describing the components of arrangement or methods, terms such as first, second, A, B, (a), and (b) may be used. These terms are merely intended to distinguish the components from other components, and the terms do not limit the nature, order or sequence of the components.

And, when a component is described as being 'connected', 'coupled' or 'interconnected' to another component, the component is not only directly connected, coupled or interconnected to the other component, but may also include cases of being 'connected', 'coupled', or 'interconnected' due that another component between that other components.

In addition, when described as being formed or arranged in "on (above)" or "below (under)" of each component, "on (above)" or "below (under)" means that it includes not only the case where the two components are directly in contact with, but also the case where one or more other components are formed or arranged between the two components. In addition, when expressed as "on (above)" or "below (under)", the meaning of not only an upward direction but also a downward direction based on one component may be included.

<FIG> illustrates a cell balancing module.

The cell balancing module <NUM> comprises a main board <NUM>, a sub-board <NUM>, and a connector <NUM>, and may further includes a control unit <NUM> and a heat dissipation unit <NUM>.

Cell balancing for a battery is to control the voltage of each cell being connected, as shown in <FIG>, to be the same, and when the cell balancing is performed all of the voltages being charged in each cell become equal (V1=V2=V3=Vn). For cell balancing, the cell balancing module <NUM> may include resistors R1 to R3 that consume the voltage of the cell and a control unit <NUM> for controlling the voltage consumption of the cell using each resistor. For cell balancing, a cell of the cell balancing module <NUM> may include resistors R1 to R3 that consume voltage and a control unit <NUM> for controlling voltage consumption of the cell by using each resistor. Among the resistors connected to each cell, a resistor connected to the cell whose voltage is higher than the voltage of the other cell is connected to the cell to form a closed loop, so that current flows, and the voltage of the cell is consumed through the flowing current, thereby balancing the cells. This is called a passive balancing.

For cell balancing, two resistors <NUM> and <NUM> are connected to each cell <NUM>, and the voltage of the cell is consumed through a current flowing therethrough. The cell balancing operation is controlled through the on/off of the switch <NUM> by the control of the control unit <NUM>.

When cell balancing is performed, the relationship between the current flowing through the resistor and the balancing time is shown in <FIG>. As the current flowing through the resistor is increased, the voltage change in each cell has a very fast response speed. In addition, as shown in <FIG>, when the resistor <NUM> is mounted on the substrate <NUM> and cell balancing is performed by the control of the control units <NUM> and <NUM>, as the number of resistors <NUM> increases, power consumption can be increased, and thus, the balancing time can be reduced.

However, when the current in each resistor <NUM> is increased, the power consumption in each resistor increases, so that a rapid temperature rise may occur inside the resistor and the module. When the number of resistors <NUM> is increased, the size of the substrate <NUM> increases according to the space occupied by the resistors, and accordingly, the size of the case also increases, resulting in an increase in cost. In addition, when a plurality of resistors <NUM> are simultaneously used in a limited space, hot spots may occur due to an increase in heat density generated in the resistors, thereby causing a risk of failure or fire.

For efficient cell balancing, the cell balancing module <NUM> includes a stack structure having one or more sub-boards <NUM> being formed and spaced apart from each other by a predetermined interval in an upper portion of the main substrate <NUM> on which a plurality of cell balancing resistors <NUM> are mounted.

The sub-board <NUM> and the main board <NUM> are electrically connected to each other through one or more connectors <NUM>, and the connector <NUM> supports the sub-board <NUM> so that the sub-board <NUM> can be spaced apart from the main board <NUM>.

Since it is possible to expand the mounting space by mounting the cell balancing resistors <NUM> and <NUM> on the main board <NUM> and the sub-board <NUM>, respectively, efficient design of cell balancing resistors for cell balancing is possible. The cell balancing resistors <NUM> and <NUM> mounted on the main board <NUM> and the sub-board <NUM> may have two cell balancing resistors connected in series for each battery cell so that a voltage flowing from each battery cell can be consumed. On the main board <NUM> and the sub-board <NUM>, an on/off switch may be mounted to control the connection between the two cell balancing resistors and the cell. On/off of the corresponding switch may be controlled by the control unit <NUM>.

The connector <NUM> serves to support the stack structure of the sub-board <NUM> and to connect the sub-board <NUM> and the main board <NUM>. At this time, the connector <NUM> may have a patterned connection line therein, and may connect the main board <NUM> and the sub-board <NUM> through the patterned connection line therein. The control unit <NUM> for controlling power consumption in the cell balancing resistors <NUM> and <NUM> may be mounted on the main board <NUM> as shown in <FIG>.

The control unit <NUM> being mounted on the main board <NUM>, may control not only the connection of the cell balancing resistor <NUM> mounted on the sub-board <NUM> but also the cell balancing resistor <NUM> mounted on the main board <NUM>. That is, one control unit <NUM> may control the connection of all cell balancing resistors mounted on the cell balancing module <NUM>. It is natural that multiple control units <NUM> may be used depending on the number of cell balancing resistors or the performance or control design of the control unit <NUM>.

In order for the control unit <NUM> to control the connection of the cell balancing resistor <NUM> mounted on the sub-board <NUM>, the control signal of the control unit <NUM> needs to be transferred to the cell balancing resistor <NUM> mounted on the sub-board <NUM>, so a conductive line is required to connect them. The connector <NUM> includes a connection line being patterned such as a penetrating electrode therein, and may connect the electrode of the main board <NUM> and the electrode of the sub-board <NUM> through the connection line. A feed line and a ground line are formed in the connector <NUM> so that a closed loop including a resistor may be formed. The connector <NUM> formed with a connection line patterned therein and formed with terminals, at both ends thereof, where the main board <NUM> and the sub-board <NUM> are connected can be easily coupled by connecting the corresponding terminal to the main board <NUM> and the sub-board <NUM>. Through this, the manufacturing process of the cell balancing module <NUM> becomes simplified, and the process speed can be increased.

In mounting the cell balancing resistor, as shown in <FIG>, the cell balancing resistors <NUM> and <NUM> may be mounted on the main board <NUM> in both directions of the control unit <NUM>, each of the sub-boards <NUM> and <NUM> are stacked on the main board <NUM> on which each cell balancing resistor is mounted, and cell balancing resistors <NUM> and <NUM> may be mounted on each of the sub-boards <NUM> and <NUM>.

As shown in <FIG>, the sub-board being stacked on the main board <NUM> may be in plural as <NUM> and <NUM>, and a connector <NUM> is formed between the sub-boards <NUM> and <NUM> adjacent to each other so that the sub-boards <NUM> and <NUM> adjacent to each other may be formed to be spaced apart from each other by a predetermined interval. By stacking the sub-board in multiple layers instead of one layer, the space for mounting the cell balancing resistor can be further expanded. Each of the sub-boards <NUM> and <NUM> are spaced apart from each other by a connector <NUM>, and may be connected to each other through the connector <NUM>.

As described above, various cell balancing resistor designs are possible by using a stack structure in which the sub-board <NUM> is stacked on an upper portion of the main board <NUM>. At least one or more of an interval between cell balancing resistors, the number of cell balancing resistors, and the number of sub-boards may vary according to heat density, balancing time, the number of cells performing balancing, or the space of a cell balancing module.

<FIG>, <FIG> and <FIG> illustrate a cell balancing module not covered by the present invention. Conversely, in an embodiment of the invention, as shown in <FIG>, the plurality of cell balancing resistors <NUM> and <NUM> being formed on the main substrate <NUM> and the plurality of cell balancing resistors <NUM> and <NUM> being formed on the sub-boards <NUM> and <NUM> are and must be alternately disposed to cross each other so that positions are not overlapped with each other. Since there is no cell balancing resistor being overlapped in up and down direction, the heat density is reduced by half. When the heat density is reduced by half, the risk of heat generation can be lowered, and a large current can be used. Through this, the current can be increased four times compared to the existing one, and as shown in <FIG>, since the cell balancing time is inversely proportional to the square of the magnitude of the current, the cell balancing time can be reduced by <NUM>/<NUM>.

Or, as shown in <FIG>, the number of cell balancing resistors mounted on the cell balancing module <NUM> may be doubled by stacking the sub-boards <NUM> and <NUM> on the main board <NUM>. In this case, unlike <FIG>, the heat density is the same, but the number of cells capable of balancing the existing cells can be doubled. That is, the number of cells capable of cell balancing can be increased with one cell balancing module <NUM>.

In addition, as shown in <FIG>, the number of cell balancing resistors being mounted on the main board <NUM> is reduced by half, but a space in which the cell balancing resistor is mounted may be formed in only one direction of the control unit <NUM> by laminating the sub-board <NUM>. In this case, unlike <FIG>, the heat generation density is the same as before, but the size of the substrate can be reduced. That is, since the overall size of the cell balancing module <NUM> can be reduced, miniaturization is possible.

As shown in <FIG>, the spacing between cell balancing resistors, the number of cell balancing resistors, and the number of sub-boards are determined depending on the heat density, balancing time, the number of cells performing balancing, or the space of the cell balancing module, and accordingly, the cell balancing module <NUM> may be designed.

In addition, as shown in <FIG>, the number of resistors may be increased using a stack structure, but different resistor values of the cell balancing resistor may be applied.

First, by using the stack structure, the power consumed by all resistors is maintained the same, and the resistor value of each resistor can be reduced in half (<NUM>). In this case, although the current flowing through the cell balancing circuit is the same, individual resistor values are reduced to reduce individual heat generation. That is, the heat density can be reduced.

Or, each resistor value may be reduced while maintaining the same power consumption (<NUM>). In this case, the current flowing through the cell balancing circuit is doubled, and thus, the cell balancing time can be shortened.

The sub-board <NUM> is formed to be spaced apart from the main substrate <NUM>, and a plurality of cell balancing resistors <NUM> may be mounted on a surface facing or opposite to the main substrate <NUM>. As shown in <FIG>, the cell balancing resistor <NUM> is mounted on the opposite surface of the surface facing the main board <NUM>, or as shown in <FIG>, the cell balancing resistor <NUM> may be mounted on a surface facing the main substrate <NUM>.

At this time, in the sub-board <NUM>, the heat dissipation unit <NUM> may be formed on a surface on which the plurality of cell balancing resistors <NUM> is not mounted. When the heat dissipation unit <NUM> is formed on the sub-board <NUM>, in order to increase heat dissipation efficiency, the heat dissipation unit <NUM> may be formed to face the outside. As such, when the heat dissipation unit <NUM> is formed outside, that is, in an upper direction of the main substrate <NUM>, the cell balancing resistor <NUM> being mounted on the sub-board <NUM> may be mounted on a surface facing the main board <NUM>. When the heat dissipation unit <NUM> is not formed, the cell balancing resistor <NUM> being mounted on the sub-board <NUM> may be mounted on a surface opposite to the surface facing the main board <NUM> so as to form a distance between the cell balancing resistors farther.

It is natural that the sub-board <NUM> on which the heat dissipation unit <NUM> is formed may also be stacked in a plurality of layers <NUM> and <NUM> as shown in <FIG>.

The cell balancing module <NUM> formed as described above may be manufactured through the following process.

First, a cell balancing resistor is mounted on one or more sub-boards, and a connector is connected to form a resistor module, and the cell balancing resistor and the control unit <NUM> for controlling the cell balancing resistor is mounted on the main board, and then the resistor module is stacked on the cell balancing resistor of the main board, and thereby the cell balancing module <NUM> may be manufactured.

More specifically, as shown in <FIG>, cell balancing resistors may be mounted on each sub-board stacked on the main board and connectors may be connected (<NUM>, <NUM>, and <NUM>).

Here, a process of forming a heat sink such as a heat dissipation unit on the sub-board may be performed. The heat sink may be formed at an upper portion or a lower portion of the sub-board. In addition, the connector may be an interface connector in which a patterned connection line is formed, and may be connected to the sub-board through soldering. Thereafter, a resistor module may be formed (<NUM>) through reflow soldering (<NUM>) for the sub-boards. Here, the reflow soldering is a process of supplying an appropriate amount of solder to a joint in advance, and then melting the solder by a heat source from the outside to perform soldering.

Thereafter, the necessary parts such as the cell balancing resistor and the control unit <NUM> are mounted on the main board (<NUM>), and the cell balancing module manufacturing process may be completed (<NUM>) via reflow soldering of the resistor module on the main board (<NUM>).

Claim 1:
A cell balancing module comprising:
a main board (<NUM>) on which a plurality of first cell balancing resistors (<NUM>) are mounted;
at least one sub-board (<NUM>) on which a plurality of second cell balancing resistors (<NUM>) are mounted and which is mounted above the main board (<NUM>) while being spaced a predetermined distance apart therefrom; and
at least one connector (<NUM>) supporting the sub-board (<NUM>) to be spaced apart from the main board (<NUM>) and electrically connecting the sub-board (<NUM>) to the main board (<NUM>),
characterized in that
the plurality of first cell balancing resistors (<NUM>) mounted on the main board (<NUM>) and the plurality of second cell balancing resistors (<NUM>) mounted on the sub-board (<NUM>) are alternately disposed so that positions are not overlapped with each other.