WO2012171197A1

WO2012171197A1 - Apparatus and method for equalizing controlling lithium battery

Info

Publication number: WO2012171197A1
Application number: PCT/CN2011/075802
Authority: WO
Inventors: 刘伟; 刘新宇; 水伟
Original assignee: 华为技术有限公司
Priority date: 2011-06-16
Filing date: 2011-06-16
Publication date: 2012-12-20
Also published as: CN102232261B; CN102232261A

Abstract

The invention, which belongs to the field of electric energy storage and is designed to solve the problem of electronic equipment abnormality caused by over-temperature of a shunt unit during equalizing a lithium battery pack, discloses an apparatus and method for equalizing controlling a lithium battery. The apparatus for equalizing controlling the lithium battery comprises a battery pack, a scheduling unit, a shunt unit and a voltage collecting unit which is provided at one side of the battery cells in the battery pack, wherein the battery cells are connected in parallel with the shunt circuits in the shunt unit, the shunt unit and the voltage collecting unit are connected to the scheduling unit respectively, and a temperature collecting unit connected with the scheduling unit is provided at one side of the shunt unit.

Description

Lithium battery equalization control device and method

The present invention relates to a lithium battery charging apparatus and method, and more particularly to a lithium battery equalization control apparatus and method.

Background technique

Lithium batteries are widely used in electronic equipment due to their high energy, long cycle life, high energy density and stable operating voltage. When a plurality of lithium batteries are connected in series to form a battery pack, it is necessary to prevent over-discharge and over-charging of the unit cells in consideration of safety and cycle performance of the lithium battery. Therefore, the capacity of the battery pack depends on the capacity of each single battery, wherein the capacity of the lithium battery is related to its voltage value. In order to charge the battery pack during the charging of the battery pack, each unit cell needs to reach the rated voltage. When a single battery has a lower capacity, its voltage is lower than that of other single cells. At this time, in order to reach the rated voltage of the battery pack, overcharging of other single cells may occur, which may cause lithium battery explosion. .

In order to avoid the above situation, in the prior art, a lithium battery equalization control device, as shown in FIG. 1, includes a battery pack, a shunt unit, a voltage detecting unit and a control unit; each of the single cells and a shunt in the battery pack The circuit is connected in parallel, and the shunt circuit is provided with an energy consuming component; the shunt circuit is connected to the control unit; the control unit is connected to the voltage detecting unit; and the voltage detecting unit is connected to the single battery in the battery pack.

When charging the battery pack in the electronic device, detecting the voltage of each of the single cells through the voltage collecting unit; when the difference between the voltage of one of the single cells and the voltage of the other cells is greater than a set value, Turn on the shunt circuit. For example, when the voltage of the single cell 1 and the voltage of the cell 4 differ by 20 millivolts, the control unit turns on the shunt circuit 4 corresponding to the cell 4, and the energy consuming component shunts the charging current of the cell 4. The charging speed of the unit cell 4 is lowered, and the unit cell 1 maintains the original charging speed; when the difference is reduced to 5 mV, the shunt circuit 4 is turned off, and the charging speed of the unit cell 4 is restored to achieve a balanced effect. In the above process, the electric energy is consumed by the shunting unit to generate heat. When the plurality of shunting circuits are simultaneously turned on, the generated heat is increased, and the heat is not dissipated in time, which may cause the electronic device to function abnormally.

Summary of the invention

Embodiments of the present invention provide a lithium battery equalization control apparatus and method for preventing overheating of an electronic device during a lithium battery equalization process.

In order to achieve the above object, embodiments of the present invention use the following technical solutions:

A lithium battery equalization control device, comprising a battery pack, a dispatching unit, a shunting unit and a voltage collecting unit, wherein a voltage collecting unit is disposed on a side of the single battery in the battery pack; and the single battery and the shunt unit The shunting circuit is connected in parallel; the shunting unit and the voltage collecting unit are respectively connected to the dispatching unit; and the temperature collecting unit is disposed on one side of the shunting unit; the temperature collecting unit is connected to the dispatching unit;

The battery pack is composed of at least two single cells connected in series;

The shunting unit is configured to shunt a charging current to reduce a charging speed of the single battery, the shunting unit includes at least two shunt circuits, and the shunting circuit includes an energy consuming component;

The voltage clamping unit is configured to collect voltage values of the single cells;

The temperature collecting unit is configured to collect temperature values of the shunting unit;

The scheduling unit is configured to control on-off of the shunt circuit in the shunting unit according to the voltage value and the temperature value collected by the dimming to achieve equalization of the capacity of the single cell and prevent the shunting unit from overheating.

A lithium battery equalization control method includes:

Setting a superheat temperature value of the shunt unit in the scheduling unit;

The temperature collecting unit obtains a current temperature value of the shunting unit;

The scheduling unit determines whether the current temperature value of the shunt unit is greater than the set superheat temperature value;

If the scheduling unit determines that the current temperature value of the shunt unit is greater than the set superheat temperature value, the shunt circuit is disconnected, the heat generated by the shunt circuit in the shunt unit is reduced, and the shunt unit temperature is reduced. The lithium battery equalization control device and method provided by the embodiment of the invention collects the temperature of the shunt unit through the temperature collecting unit, and when the temperature exceeds the preset superheat temperature value, disconnects the shunt circuit corresponding to the single cell, and reduces The heat generated by the shunt unit prevents overheating of the electronic device when the cell is balanced, and improves the stability of the electronic device.

DRAWINGS

1 is a schematic structural view of a lithium battery equalization control device in the background art of the present invention;

2 is a schematic structural diagram of a lithium battery equalization control device according to an embodiment of the present invention; FIG. 3 is a flowchart of a lithium battery equalization control method according to an embodiment of the present invention; FIG. 4 is a lithium battery equalization control method according to an embodiment of the present invention; a flow chart for controlling the shunt circuit;

FIG. 5 is a flowchart of a disconnection circuit of a lithium battery equalization control method when the temperature is too high according to an embodiment of the present invention; FIG.

FIG. 6 is a flow chart of restoring a shunt of a lithium battery equalization control method according to an embodiment of the present invention.

detailed description

A lithium battery equalization control apparatus and method of the present invention will be described in detail below with reference to the accompanying drawings.

A lithium battery equalization control device, as shown in FIG. 2, includes a battery pack, a dispatching unit, a shunting unit, and a voltage collecting unit, and a voltage collecting unit is disposed on a side of the single battery in the battery pack; The battery and the shunting circuit in the shunting unit are connected in parallel; the shunting unit and the voltage collecting unit are respectively connected to the dispatching unit; and the temperature collecting unit is disposed on one side of the shunting unit; the temperature collecting unit is connected to the dispatching unit;

The battery pack is composed of at least two single cells connected in series;

The voltage clamping unit is configured to collect voltage values of the single cells; The temperature collecting unit is configured to collect temperature values of the shunting unit;

The voltage clamping unit collects the voltage value of each single battery in the battery group, and sends the voltage value to the scheduling unit; the temperature collecting unit collects the temperature of the dividing unit, and sends the temperature value to the scheduling unit; The shunt unit is controlled according to the received voltage value and the temperature value, and the battery pack is equalized during the charging process to prevent the heat generated by the shunt unit from being excessively caused by the shunt unit during the equalization process, thereby improving the charging of the electronic device. stability.

Corresponding to the above-mentioned lithium battery equalization control device, the present invention also provides a lithium battery equalization control method, as shown in FIG. 3, including:

Step 3 00, setting the superheat temperature value of the shunt unit in the scheduling unit

Set the overheating temperature value of the shunt unit in the dispatching unit. In order to prevent the electronic equipment from being damaged due to excessive temperature, the temperature value is generally set within the safe temperature range of the electronic device. For example, the superheating temperature value can be set to 80 degrees.

In order to achieve the balance of the cell capacity, it is necessary to determine which cells need to be shunted according to the voltage difference between the cells, so as to slow down the charging speed, as shown in the figure.

4 is shown.

Step 4 00, setting a voltage difference value for shunting the single battery in the scheduling unit, which is called a shunt voltage difference

In order to balance the battery capacity of the electronic device, it is necessary to determine whether to open the shunt circuit for shunting according to the voltage value of the battery cells in the battery pack, and to shunt the cells in the battery pack.

Set the voltage difference of the single cell when the shunt circuit is turned on. The voltage difference is called the shunt voltage difference. For example, set the shunt voltage difference to 20 mV.

Step 4 01. The voltage collecting unit obtains the voltage value of each single battery, and determines the single battery corresponding to the minimum voltage value, which is called a short-plate single battery.

The scheduling unit acquires voltage values of the respective single cells collected by the voltage collecting unit, The single cell corresponding to the minimum voltage value is referred to as a short-board single cell, and the other single cells are shunted according to the short-board single cell to achieve equalization of the cell capacity, as shown in FIG. The unit cell 1 is the short-plate single cell having a voltage value of 3000 mV.

Step 4 02, the scheduling unit determines whether the voltage difference between the single battery and the short battery unit is greater than the voltage difference of the shunt

Determining, according to the voltage value collected by the voltage collecting unit, whether there is a single cell having a voltage difference from the short-plate single cell greater than a shunt voltage difference, for example, the voltage value of the single cell 2 is 3 300 mV, The cell 3 has a voltage value of 3 027 mV, the cell 4 has a voltage of 3 001 mV, and the cell 5 has a voltage of 32 0 3 mV.

Step 4 03: If the voltage difference between the single cell and the short cell is greater than the shunt voltage difference, turn on the shunt circuit corresponding to the cell, shunt the cell, and reduce the charging of the cell. Speed

According to the voltage value of the single cell, determining a cell voltage greater than the difference of the shunt voltage, for example, the voltage difference between the cell 2, the cell 3, and the cell 5 and the short cell is greater than 20 mV, Therefore, the scheduling unit controls the shunt circuit corresponding to the single battery to be turned on, that is, the shunt circuit 2, the shunt circuit 3, and the shunt circuit 5 are turned on, shunting the single cells, and reducing the charging speed of the corresponding single cells. At this time, in the shunt circuit, the energy is dissipated by the energy consuming element, heat is generated on the energy consuming element, and the temperature rises.

Step 3 01. The temperature collection unit obtains the current temperature value of the shunt unit.

After the shunting, the temperature collection unit on the side of the diverting unit is collected at intervals of, for example, 82 degrees.

Step 302: The scheduling unit determines whether the current temperature value of the shunt unit is greater than the set superheat temperature value.

The dispatch unit compares the current temperature value with the superheat temperature value to determine that 82 degrees is greater than the set superheat temperature value of 80 degrees.

Step 303: If the scheduling unit determines that the current temperature value of the shunt unit is greater than the set superheat temperature value, disconnecting the shunt circuit to reduce the shunt circuit generated by the shunt unit Heat, lower the temperature of the split unit

When the current temperature value collected is greater than the overheat temperature value, in order to prevent damage to the electronic equipment due to excessive temperature, the shunt circuit needs to be controlled to reduce the heat generated by the shunt circuit, as shown in FIG.

Step 510: The scheduling unit compares the voltage difference between the short-cell single-cell and the single-cell connected to the shunt circuit according to the voltage value of the single-cell battery collected by the voltage-collecting unit, according to the obtained voltage of the single-cell battery Value, comparing the voltage difference between the short-cell single cell and the single-cell connected to the plurality of shunt circuits, for example, the voltage difference between the single-cell battery 2 and the short-plate single-cell battery is 300 mV, the single cell 3 The voltage difference between the short cell and the single cell is 27 mV, and the voltage difference between the cell 5 and the short cell is 2 03 volts.

Step 5 01: Determine a cell having the smallest voltage difference from the short cell single cell, and determine a cell having the smallest voltage difference according to the voltage difference, that is, a cell

3.

Step 5 02. Disconnect the shunt circuit of the single cell to reduce the heat generated by the shunt unit.

Because the voltage difference between the single cell 3 and the short cell is the smallest, it can be determined that the capacity difference between the cell 3 and the short cell is small, and the shunt circuit 3 of the cell 3 is disconnected. In order to reduce the heat generated in the shunt circuit, at this time, as the energy-consuming element generating heat is reduced, the temperature on the side of the shunt unit is gradually decreased.

After a period of time, for example two minutes, the temperature of the shunt unit is again collected. If the temperature still does not reach a predetermined value, then according to the above steps, the shunt circuit of a single battery is disconnected.

Further, in order to improve the equalization effect between the individual cells, when the temperature drops to a preset value, the shunt circuit is reconnected to shunt the cells, as shown in FIG. 6, including:

Step 6 00, setting a temperature value of the shunting circuit in the shunting unit to be re-connected in the scheduling unit, which is called a restarting temperature value.

After step 300, setting a shunt circuit in the shunt circuit to be turned back on The preset value of the temperature, which is called the restart temperature value, for example, the restart temperature value is 60 degrees.

After the scheduling unit determines that the current temperature value of the shunting unit is greater than the set superheating temperature value, the shunt circuit is disconnected, the heat generated by the shunting circuit in the shunting unit is reduced, and after the shunting unit temperature is lowered, the method further includes:

Step 6 01: Determine whether the current temperature value of the shunt unit is less than the restart temperature value. The temperature unit collects the current temperature value of the shunt unit, for example, the current temperature value is 58 degrees, and determines whether the collected temperature value is less than Restart the temperature value.

Step 6 02. If the current temperature value of the shunt unit is less than the restart temperature value, the voltage difference between the single-cell battery and the single-cell battery that is not connected to the shunt circuit

The collected temperature of 58 degrees is less than the set minimum temperature value of 60 degrees, and the voltage difference between the short-plate single cell and the single cell that is not connected to the shunt circuit is compared, for example, the single cell 3 is in the shunt When the temperature value of the unit is greater than the superheat temperature value, the shunt unit 3 corresponding to the unit cell 3 has been disconnected.

Step 6 03. Determine a single cell that has a voltage difference from the short-board single cell that is greater than a shunt voltage difference.

According to the comparison of the voltage difference, the voltage of the single cell 3 is 3027 mV, and the voltage difference of 3000 mV from the short cell unit voltage is 27 mV, which is greater than the shunt voltage difference of 20 mV.

Step 6 04. Connect the shunt circuit corresponding to the single battery to re-divide the single battery in the battery pack.

The shunt circuit 3 corresponding to the unit cell 3 is reconnected, and the unit cell 3 is re-divided to equalize the capacity of the unit cell.

When there are multiple cells in the battery pack that need to be shunted, when the temperature value of the shunt cell is less than the restart temperature value, the cell with a voltage difference between the short cell and the cell is greater than the shunt voltage difference. The corresponding shunt circuits are all turned on, and the shunting is continued to balance the capacities of the single cells in the battery pack and the short cell single cells.

A lithium battery equalization control device and method provided by an embodiment of the present invention, the temperature of the shunt unit is collected by a temperature collecting unit, when the temperature exceeds a preset superheat temperature value, Disconnect the shunt circuit corresponding to the single cell, reduce the heat generated by the shunt unit, prevent the electronic device from overheating when the cell is balanced, and improve the stability of the electronic device.

The above is only the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or substitutions within the technical scope of the present invention. It should be covered by the scope of the present invention. Therefore, the scope of the invention should be determined by the scope of the claims.

Claims

A lithium battery equalization control device, comprising a battery pack, a dispatching unit, a shunting unit and a voltage collecting unit, wherein a voltage collecting unit is disposed on a side of the single battery in the battery pack; and the single battery and the shunt unit The shunting circuit is connected in parallel; the shunting unit and the voltage collecting unit are respectively connected to the dispatching unit, wherein the temperature collecting unit is disposed on one side of the shunting unit; the temperature collecting unit is connected to the dispatching unit;

The battery pack is composed of at least two single cells connected in series;

The shunting unit is configured to divide a charging current to reduce a charging speed of the single battery, the shunting unit includes at least two shunting circuits, the shunting circuit includes an energy consuming component, and the voltage collecting unit is configured to collect a single cell The voltage value of the battery;

The temperature collecting unit is configured to collect a temperature value of the shunting unit;

The scheduling unit is configured to control on and off of the shunting circuit in the shunting unit according to the collected voltage value and the temperature value, so as to achieve equalization of the capacity of the single cell and prevent the shunting unit from overheating.

2. A lithium battery equalization control method, characterized in that:

Setting a superheat temperature value of the shunt unit in the scheduling unit;

The temperature collecting unit acquires a current temperature value of the shunting unit;

If the scheduling unit determines that the current temperature value of the shunt unit is greater than the set superheat temperature value, the shunt circuit is turned off, the heat generated by the shunt circuit in the shunt unit is reduced, and the shunt unit temperature is lowered.

The lithium battery equalization control method according to claim 2, wherein after the setting the superheat temperature value of the shunt unit in the scheduling unit, the method further comprises: setting, in the scheduling unit, the single cell The voltage difference of the shunt is called the shunt voltage difference;

The voltage collecting unit obtains the voltage value of each single battery, and determines the single battery corresponding to the minimum voltage value, which is called a short-board single battery;

The scheduling unit determines whether the voltage difference between the single battery and the short battery unit is greater than Current voltage difference

If the voltage difference between the single cell and the short cell is greater than the shunt voltage difference, the shunt circuit corresponding to the cell is turned on, and the cell is shunted to reduce the charging speed of the cell.

The lithium battery equalization control method according to claim 2, wherein if the scheduling unit determines that the current temperature value of the shunt unit is greater than the set superheat temperature value, the shunt circuit is disconnected, and the shunt unit is reduced. The heat generated by the shunt circuit reduces the temperature of the shunt unit, including:

The scheduling unit compares the voltage difference between the single-cell battery and the single-cell connected to the shunt circuit according to the voltage value of the single cell collected by the voltage collecting unit;

Determining a single cell having the smallest difference from the voltage of the short-plate single cell;

Disconnect the shunt circuit of the single cell to reduce the heat generated by the shunt unit.

5. The lithium battery equalization control method according to claim 2, further comprising:

Setting, in the scheduling unit, a temperature value in which the shunt circuit is reconnected in the shunting unit, which is called a restart temperature value;

If the scheduling unit determines that the current temperature value of the shunting unit is greater than the set superheating temperature value, the shunt circuit is disconnected, the heat generated by the shunting circuit in the shunting unit is reduced, and after the shunting unit temperature is decreased, the method further includes:

Determining whether the current temperature value of the shunt unit is less than a restart temperature value;

If the current temperature value of the shunt unit is less than the restart temperature value, compare the voltage difference between the short-board single-cell battery and the single-cell battery that is not turned on;

Determining a cell with a voltage difference between the short cell and the cell that is greater than a voltage difference of the shunt; connecting the shunt circuit corresponding to the cell to re-divide the cell in the battery.