TWI723319B - Battery energy balance compensation system - Google Patents

Abstract

A battery energy balance compensation system is disclosed herein and includes a battery set, a switch array, a current meter and a microcontroller. The battery set includes a plurality of batteries. The switch array is electrically connected to the battery set. The current meter is electrically connected to the battery set and the switch array and is configured to detect the current in each of the batteries of the batter set. The current meter is also used to detect an overall current of the switch array. The microcontroller includes a current switch, consisting of a plurality adjusting units, and is electrically connected to the current meter and the current switch and calculates an inner resistor in each of the batteries so as to turn on or off each of the adjusting units of the current switch to alternatively compensates at least one of the battery energy of the plurality of batteries such that the battery energy of each batteries of the battery set is balance.

Description

Battery cell balance compensation system

The present invention relates to a battery power balance compensation system, in particular to a battery power balance compensation system that can balance and compensate the power of each cell in a battery pack.

With the advancement of science and technology, the production and research of lithium batteries has made great breakthroughs, because lithium batteries have the characteristics of stable discharge voltage, low self-discharge rate, wide operating temperature range, no memory effect, long storage life, light weight and small size. , Has gradually replaced the traditional nickel-cadmium batteries or lead-acid batteries.

As the application of lithium batteries becomes more and more widespread, the management of batteries has become a very important technology in various devices. Because the chemical reaction inside the lithium battery is very complicated, while continuously improving the performance of the battery, the management technology and use of the battery are also continuously researched to increase the service life of the battery and improve the efficiency of the battery. Give full play to battery performance.

The battery management system (Battery Management System, BMS) is a system that balances and manages the power of the cells in the battery pack. It has the function of measuring the voltage of the cells to prevent or avoid over Abnormal conditions such as discharging, overcharging, and over temperature appear. It involves microcomputer technology and detection technology, which can promote the battery core to be in the best working condition, reduce operating costs and increase service life.

However, the general active balance battery management system often fails to take into account the state of charge of each battery cell and provide the most suitable balance current when performing battery balancing, so as to achieve the purpose of protecting the battery cell and prolonging the service life. In other words , Because the balance current cannot be adjusted for different power states (or cells of different nature), and the characteristics of cells with different voltage levels, it is likely to damage the cells due to excessive balance current, or delay due to excessive balance current To achieve the purpose of battery balance.

There are many factors that cause the unbalance of the battery cells in the battery pack, such as self-discharge. Some battery cells self-discharge more and some battery cells less self-discharge. The battery self-discharges less and the voltage is higher, and it will be fully charged faster when charging; the battery self-discharges more, the voltage is lower, and the charging time is slow.

Furthermore, in the past, when using an external power supply or battery pack power supply, the cells would be charged with a fixed voltage/current (cell balance). The cell to be charged and the input power supply voltage tend to have an excessive voltage difference, resulting in excessive Current injection and high current input are also easy to damage the switch (chip (IC) burn out).

Therefore, it is necessary to design a novel battery management system to address the above-mentioned problems, which can manage the battery aging problem, and give a matching current to a single battery cell. In addition to avoiding the switch burnout, it can also extend the overall battery pack Service life.

The purpose of the present invention is to disclose a battery power balance compensation system to perform power compensation for cells of different voltage levels to achieve the purpose of battery global balance.

According to the above objective, the present invention provides a battery cell balance compensation system, including: a battery pack including a plurality of battery cells; a plurality of battery selection switches, each battery cell corresponding to each battery selection switch; a voltage measurement unit battery Connect the battery pack to estimate the power of the battery cells; a processor is electrically connected to the voltage measurement unit and the battery selection switches; a power compensation module is electrically connected to the processor, and the processor confirms the power of each battery cell , The power compensation module is controlled to perform power compensation for the designated cells through the battery selection switch. The power compensation module includes a current selection switch, which is composed of a plurality of adjustment units, and the power compensation mode is adjusted by the adjustment units. The current size of the cell specified by the group input.

In the battery cell balance compensation system, each adjustment unit includes a current-limiting resistor and a switch.

The battery power balance compensation system includes a physical measurement unit for obtaining an internal resistance value of each battery cell

In the battery cell balance compensation system, the processor controls the current selection switch to switch the adjustment unit according to the voltage of the battery cell to input the matching power or current for the specific battery cell.

In the battery cell balance compensation system, the processor switches the balance switch of each adjustment unit to provide a balance current.

In the battery cell balance compensation system, the formula for calculating the balance current is: I _BAL =(V _DC -V _BAT )/(R _SEL +R _GEAR ), where V _DC is the power supply voltage of the power compensation module, V _BAT is the voltage value of a balanced battery, R _{SEL is} the resistance value of the balancing switch, and R _{GEAR is} the resistance of the current selection switch.

In the battery cell balance compensation system, the power compensation module includes a power conversion element and is electrically connected to a power supply module.

In the battery cell balance compensation system, the power conversion element adjusts the input voltage of the power supply module to match the output current of the power compensation module.

In the battery cell balance compensation system, the power supply module is derived from an external power source or from the battery pack itself.

In the battery cell balance compensation system, the physical measurement unit can be an ammeter.

Accordingly, the present invention adjusts the current flowing through the balance switch by calculating a balance current, so as to avoid the balance switch from burning out. In addition, through the activation and deactivation of the current selection switch, the amount of current input to the specified cell can be controlled.

As mentioned above, the battery cell balance compensation system of the present invention is an active energy management system, which can balance, compensate and manage the power of each cell with its own battery pack or external power supply, so that the battery Each battery cell in the group can maximize its own power. At the same time, the measured voltage value of each cell is transmitted to the processor through the voltage measurement unit, so that the processor controls the opening and closing of each balance switch in the current selection switch, and then adjusts the current selection switch to facilitate The designated battery cells that need to be charged are given matching currents to achieve the purpose of balancing the power of each battery cell in the battery pack.

10: Battery cell balance compensation system

101: battery pack

102: Battery selection switch

103: Voltage measurement unit

104: processor

105: Power compensation module

106: Current selection switch

107: Battery

108: adjustment unit

109: current limiting resistor

110: Balance switch

111: External power supply

112: Power Conversion Components

113: physical measurement unit

114: Power supply module

Figure 1 is a block diagram of the battery cell balance compensation system of the present invention.

Figure 2 is a block diagram of the battery cell balance compensation system of the present invention.

Figure 3 is a circuit diagram of the battery cell balance compensation system of the present invention.

The embodiments of the present invention will be described in detail below, and the details are also presented in related drawings. The same numbers or signs in different drawings represent the same elements or concepts. The description of the embodiments of the present invention will be carried out in conjunction with related drawings.

1 is a block diagram of the battery cell balance compensation system of the present invention, FIG. 2 is a circuit diagram of the battery cell balance compensation system of the present invention, and FIG. 3 is a block diagram of another embodiment of the battery cell balance compensation system of the present invention. As shown in FIGS. 1 and 2, the battery cell balance compensation system 10 of the present invention includes a battery pack 101, a plurality of battery selection switches 102, a voltage measurement unit 103, a processor 104, a power compensation module 105, A current selection switch 106 and a power supply module 114.

The battery pack 101 includes a plurality of battery cells 107, and each battery cell 107 corresponds to a battery selection switch 102. The battery cell 107 is preferably a secondary battery cell, which may be a lithium battery cell or a nickel battery cell, etc. It is not limited here, and the secondary batteries are connected in series.

The voltage measuring unit 103 is electrically connected to the battery pack 101 to measure the power of each battery cell 107. The processor 104 is electrically connected to the voltage measurement unit 103 and a plurality of battery selection switches 102, and the power compensation module 105 is electrically connected to the processor 104 and the battery selection switch 102. After confirming the power of each battery cell 107, the processor 104 controls the The power compensation module 105 performs power compensation on the designated battery cell 107 through the battery selection switch 102.

It should be particularly noted that the power compensation module 105 proposed in the present invention includes a current selection switch 106, which is composed of a plurality of adjustment units 108, through the plurality of adjustment units 108 to adjust the power compensation module 105 input specified The current size of the cell 107. Each adjustment unit 108 includes a current-limiting resistor 109 and a balance switch 110. The resistance value of each current-limiting resistor 109 may be the same or different. In an embodiment of the present invention, the resistance value of the current-limiting resistor 109 may be It is zero, but it is not limited here. Adjustment The unit 108 adjusts the current input to each cell 107 by the power compensation module 105 through the current-limiting resistor 109 and the balance switch 110, so that the most suitable current can be given to the cells 107 of different health levels to avoid electricity. The core 107 accelerates the aging degree due to unsuitable or unmatched current, so as to prolong the service life of the entire battery pack 101.

In different embodiments, a physical measurement unit 113 is further included to obtain an internal resistance value of each cell 107, especially when charging and discharging with a constant current or standing still, the physical measurement unit 113 can be selected through the battery The switch 102 measures the current value of each battery cell 107, and then calculates the internal resistance value of each battery cell 107 to understand the aging degree or health state of each battery cell 107. Among them, the physical measurement unit 113 can use an ammeter to measure the internal resistance of each cell 107, but it is not limited. As shown in FIG. 3, the processor 104 can use the voltage, current, and power information to calculate The internal resistance value of the cell 107 is obtained. In particular, the battery cell balance compensation system 10 proposed by the present invention obtains the internal resistance value of each battery cell 107 through the physical measurement unit 113, and can instantly understand the health status of each battery cell 107, especially for applications. In the battery management system, the physical measurement unit 113 can further monitor the health status of each battery cell 107. According to this, the battery management system can issue a warning message that a specific battery cell 107 needs to be replaced to further protect the entire battery pack 101. Overall service life.

Accordingly, the processor 104 controls the current selection switch 106 to switch the adjustment unit 108 according to the power state or voltage level of each cell 107 so that the power compensation module 105 inputs the current of a specific cell 107 to control a phase match. Within the range, according to the different internal resistance value of each cell 107, the matching current can be given through the adjusting unit 108, so as to achieve the goal of global balance. In other words, the current selection switch 106 selects different currents for balancing, and the output current can be adjusted adaptively.

In the embodiment of the present invention, the processor 104 can calculate a balance current by switching the balance switch 110 of each adjustment unit 108. Among them, the formula for calculating the balance current is: I _BAL = (V _DC -V _BAT )/(R _SEL + R _GEAR ), where V _DC is the voltage of the battery compensation module 105, and V _BAT is the voltage value of a balance battery. In a preferred embodiment, the voltage value V _{BAT of the} balance battery is the voltage value of a balance battery provided by the power supply module 114, R _SEL is the resistance value of the battery selection switch 102, and R _GEAR is the current selection switch 106 resistance value.

In addition, in an embodiment of the present invention, the power compensation module 105 includes a power conversion element 112 and is electrically connected to a power supply module 114. The power conversion element 112 is used to adjust the input voltage of the power supply module 114 to match the output current of the power compensation module 105. It should be particularly noted that the battery cell balance compensation system 10 proposed by the present invention can adjust the input voltage of the power supply module 114 to match the output current of the power compensation module 105 through the power conversion element 112. Therefore, the power supply The supply module 114 can be from an external power source 111 or from its own battery pack 101. If the battery pack 101 from itself is used as the power supply source of the power supply module 114, the entire battery pack 101 can actively adjust the balance between the power of each cell 107 of itself, and reduce the power between the cells 107. difference.

For example, if the battery pack 101 includes three cells 107, namely cell A, cell B, and cell C, the current remaining power is 50% (cell A) and 60% of the original saturation state respectively. (Cell B) and 70% (cell C), the battery cell balance compensation system 10 of the present invention can balance the cells of cell A, cell B, and cell C, so that cell A and cell B And the battery cell C is 60%. In the battery pack 101, the voltage of each cell 107 is high or low, the processor 104 will select the cell 107 with the lowest voltage to start the cell balancing work, and the power compensation module 105 knows the power of the cell 107 After balancing, the processor 104 will perform balancing work on the next cell 107.

In summary, the battery cell balance compensation system of the present invention is an active energy management system, which can use its own battery pack or an external power source as a power supply module for each The battery cells perform power balance, compensation and management, so that each battery cell in the battery pack can maximize its own power. At the same time, by measuring the current value of each cell and sending it to the processor to calculate the internal resistance of each cell, the processor controls the opening and closing of each balance switch in the current selection switch to provide an appropriate Balance the current to facilitate the power compensation for the cells that need to be charged to achieve the purpose of balancing the power of each cell in the battery pack.

The traditional battery cell balance compensation system does not have a current selection switch, and its use range is limited. For example, the voltage of the battery pack can only be adjusted between 3.6V and 4V, while the battery cell balance compensation system of the present invention can be achieved through a balance switch Achieve global battery pack balance. The so-called global battery pack balance means that when the voltage of the battery pack is too low, too much current may flow instantaneously, which will burn the switching elements in the balance circuit. At this time, you can switch the balance switch to adjust the balance current to make The use range of the battery pack is expanded to 3V~4V, and because the balance current of the battery is limited, too low cell voltage (large voltage difference) will not cause the cell to burn out or damage the switching elements in the balance circuit due to excessive current.

The above are only the preferred embodiments of the present invention and do not limit the present invention in any form. Although the present invention has been disclosed in the preferred embodiments as above, it is not intended to limit the present invention. Anyone familiar with the present invention Without departing from the scope of the technical solution of the present invention, when the technical content disclosed above can be used to make some changes or modification into equivalent embodiments with equivalent changes, but any content that does not deviate from the technical solution of the present invention, according to the technology of the present invention Essentially, any simple modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solutions of the present invention.

10: Battery cell balance compensation system

101: battery pack

102: Battery selection switch

103: Voltage measurement unit

104: processor

105: Power compensation module

106: Current selection switch

107: Battery

108: adjustment unit

109: current limiting resistor

110: Balance switch

111: External power supply

112: Power Conversion Components

113: physical measurement unit

114: Power supply module

Claims (8)

A battery cell balance compensation system, comprising: a battery pack including a plurality of battery cells; a plurality of battery selection switches, each of the battery cells corresponds to each of the battery selection switches; a voltage measurement unit electrically connected to the battery Group, used to measure the power of the batteries; a processor, electrically connected to the voltage measurement unit and the battery selection switches; a power compensation module, electrically connected to the processor, the processor confirms the batteries After the power of the cell, the power compensation module is controlled to perform power compensation on the designated cells through the battery selection switch. The power compensation module includes a current selection switch and a power conversion element. The power conversion element is electrically Connected to a power supply module. The current selection switch is composed of a plurality of adjustment units. The adjustment units include a current-limiting resistor and a balance switch. The adjustment units adjust the power compensation module input designated The current size of the battery core is matched with the different internal resistance value of each battery core to give a matching current to achieve the purpose of global balance. The battery cell balance compensation system according to claim 1, which includes a physical measurement unit for obtaining a balance current value of each of the cells. The battery cell balance compensation system according to claim 1, wherein the processor controls the current selection switch to switch the adjustment units according to the state of charge or the magnitude of the voltage of the cells. The battery power balance compensation system according to claim 1, wherein the processor switches the balance switch of each of the adjustment units to calculate the internal resistance of a battery. The battery cell balance compensation system described in claim 4, wherein the calculation formula of the balance current is: I _BAL = (V _DC -V _BAT )/(R _SEL +R _GEAR ), where the V _{DC is} the power compensation mode The voltage of the group, V _BAT is the output voltage of a balanced battery, R _{SEL is} the resistance value of the battery selection switch, and R _{GEAR is} the resistance value of the current selection switch. The battery cell balance compensation system according to claim 1, wherein the power conversion element adjusts the input voltage of the power supply module to match the output current of the power compensation module. The battery cell balance compensation system according to claim 1, wherein the power supply module is from an external power source or from the battery pack. The battery cell balance compensation system according to claim 3, wherein the physical measurement unit can be an ammeter.

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