Battery charging and discharging control circuit and method

Abstract

The present invention discloses a battery charge and discharge control circuit and method. A reference voltage generating circuit obtains a reference voltage signal based on the voltage drops of multi-channel parallel-connected batteries and the voltage drop of a voltage regulating circuit connected in parallel with the batteries. A sub-control circuit adjusts the voltage drop of the voltage regulating circuit on each channel based on the reference voltage signal to make the total voltage drop on each battery channel substantially consistent. This ensures that the current in each battery channel of a parallel battery pack is balanced during the charge and discharge process, protecting the single battery from damage and meeting the charging power supply requirements in different occasions.

Description

Technical Field

[0001] The present invention relates to the field of battery charge and discharge control, and more particularly to a battery charge and discharge control circuit and method. Background Art

[0002] In rechargeable power applications, multiple individual cells are typically connected in parallel to form a battery pack to increase capacity. However, even for batteries of the same model and batch, individual cells inevitably exhibit variations during the manufacturing process, and these variations increase with age. This variation can cause current to flow concentratedly to one or several cells during the charge and discharge process, potentially damaging them. Summary of the Invention

[0003] In view of this, an object of the present invention is to provide a battery charge and discharge control circuit and method to solve the technical problem of battery damage caused by battery differences in the prior art.

[0004] The technical solution of the present invention is to provide a battery charge and discharge control circuit for controlling multiple parallel-connected batteries, comprising a plurality of voltage regulating circuits, each corresponding to each of the multiple batteries, and each voltage regulating circuit connected in series with each of the single batteries to form a battery channel;

[0005] a reference voltage generating circuit connected to the multiple batteries and the multiple voltage regulating circuits to obtain a reference voltage signal according to the voltage drops of the multiple batteries and the voltage drops of the multiple voltage regulating circuits;

[0006] and a plurality of sub-control circuits, each corresponding one-to-one to each of the plurality of voltage regulating circuits. The plurality of sub-control circuits receive the reference voltage signal and control the voltage drops of the plurality of voltage regulating circuits accordingly, so that the total voltage drop of each battery channel is consistent with the voltage value of the reference voltage signal.

[0007] Preferably, the reference voltage generating circuit includes a first voltage generating circuit, a second voltage generating circuit and a first logic operation circuit.

[0008] When the multi-channel battery is in charging state:

[0009] The first voltage generating circuit receives the voltage drop of the multi-channel battery and selects the voltage with the maximum voltage drop value as the first voltage signal;

[0010] The second voltage generating circuit obtains a minimum voltage drop value of a voltage regulating circuit of a battery channel corresponding to the maximum voltage drop selected by the first voltage generating circuit, and uses the voltage of the minimum voltage drop value as a second voltage signal;

[0011] The logic operation circuit performs a superposition operation on the first voltage signal and the second voltage signal to obtain a first reference voltage signal.

[0012] Preferably, the reference voltage regulating circuit includes a third voltage generating circuit, a fourth voltage generating circuit and a second logic operation circuit.

[0013] When the multi-channel battery is in a discharging state:

[0014] The third voltage generating circuit receives the voltage drop of the multi-channel battery and selects the voltage with the minimum voltage drop value as the third voltage signal;

[0015] The fourth voltage generating circuit obtains a minimum voltage drop value of a voltage regulating circuit of a battery channel corresponding to the minimum voltage drop selected by the third voltage generating circuit, and uses a voltage corresponding to the minimum voltage drop value as a fourth voltage signal;

[0016] The logic operation circuit performs a subtraction operation on the third voltage signal and the fourth voltage signal to obtain a second reference voltage signal.

[0017] Preferably, the minimum voltage drop value of the voltage regulating circuit is zero or the difference between the minimum voltage drop value and zero is within a predetermined range.

[0018] Preferably, the voltage regulating circuit includes a switching circuit;

[0019] In the battery charging state, the sub-control circuit controls the switch circuit corresponding to the maximum voltage drop value to be fully turned on to obtain the minimum voltage drop value of the switch circuit.

[0020] Preferably, the voltage regulation circuit comprises an adjustable voltage source;

[0021] In the battery charging state, the sub-control circuit controls the voltage drop of the adjustable voltage source corresponding to the maximum voltage drop value to be zero, so as to obtain the minimum voltage drop value of the adjustable voltage source.

[0022] Preferably, the voltage regulating circuit includes a switching circuit;

[0023] In the battery charging state, the sub-control circuit controls the switch circuit corresponding to the minimum voltage drop value to be fully turned on to obtain the minimum voltage drop value of the switch circuit.

[0024] Preferably, the voltage regulation circuit comprises an adjustable voltage source;

[0025] In the battery discharging state, the sub-control circuit controls the voltage drop of the voltage-controlled voltage source corresponding to the minimum voltage drop value to be zero, so as to obtain the minimum voltage drop value of the adjustable voltage source.

[0026] Preferably, when the voltage regulating circuit is a switching circuit,

[0027] The sub-control circuit controls the switching state of the switch circuit according to an overvoltage protection threshold or an undervoltage protection threshold, so that the battery operates in a non-overvoltage or non-undervoltage state.

[0028] The present invention also discloses a battery charge and discharge control method for controlling multiple batteries connected in parallel, comprising the steps of:

[0029] During the charging process of the multi-channel battery,

[0030] detecting voltage drops of the multiple batteries and selecting a voltage with a maximum voltage drop value as a first voltage signal;

[0031] Utilize multiple voltage regulating circuits and the multiple batteries to be connected in series one by one to form multiple battery channels; obtain the minimum voltage drop value of the voltage regulating circuit corresponding to the maximum voltage drop value, and use the voltage of the minimum voltage drop value as the second voltage signal;

[0032] performing an addition operation on the first voltage signal and the second voltage signal to obtain a first reference voltage signal;

[0033] The voltage drop value of each voltage regulating circuit is adjusted according to the first reference voltage signal, so that the total voltage drop of each battery channel is consistent with the reference voltage signal.

[0034] Preferably, the method comprises the steps of: during the discharge process of the multi-channel battery,

[0035] detecting voltage drops of the multiple batteries and selecting a voltage with a minimum voltage drop value as the third voltage signal;

[0036] Obtaining a minimum voltage drop value of a voltage regulating circuit corresponding to the minimum voltage drop value, and using the voltage of the minimum voltage drop value as a fourth voltage signal;

[0037] performing a subtraction operation on the third voltage signal and the fourth voltage signal to obtain a second reference voltage signal;

[0038] The voltage drop value of each voltage regulating circuit is adjusted according to the second reference voltage signal, so that the total voltage drop of each battery channel is consistent with the second reference voltage signal.

[0039] Preferably, it is characterized in that the minimum voltage drop value of the voltage regulating circuit is zero or the difference between the minimum voltage drop value and zero is within a predetermined range.

[0040] With the battery charge and discharge control scheme of the present invention, a reference voltage generating circuit obtains a reference voltage value based on the voltage drops of batteries in each parallel channel and the voltage drop of a voltage regulating circuit connected in parallel with the battery. A sub-control circuit adjusts the voltage drops of the voltage regulating circuits on other parallel channels based on the reference voltage value to make the total voltage drops on each channel substantially consistent. This ensures that the currents of the batteries in each channel of the parallel battery pack are balanced during the charge and discharge process, protecting the single battery from loss, and meeting the charging power supply requirements of different occasions. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a circuit block diagram of multiple battery channels according to the present invention;

[0042] Figure 2 is a circuit block diagram of the control circuit of the present invention;

[0043] Figure 3 Based on Figure 2 A specific embodiment of;

[0044] Figure 4 Based on Figure 2 Another specific embodiment of . DETAILED DESCRIPTION

[0045] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings, but the present invention is not limited to these embodiments and covers any substitution, modification, equivalent method and solution made within the spirit and scope of the present invention.

[0046] In order to make the public have a thorough understanding of the present invention, specific details are described in detail in the following preferred embodiments of the present invention, but those skilled in the art can also fully understand the present invention without description of these details.

[0047] The present invention is described in more detail in the following paragraphs by way of example with reference to the accompanying drawings. It should be noted that the drawings are simplified and not to exact proportions, and are only used for the purpose of conveniently and clearly illustrating the embodiments of the present invention.

[0048] refer to Figure 1 is a circuit block diagram of multiple battery channels according to the present invention, Figure 2 FIG. 1 is a circuit block diagram of the control circuit of the present invention. Figure 1 and Figure 2 As shown, the battery charge and discharge control circuit is used to control multiple parallel-connected batteries, which can be labeled Bat1 through Batn. The control circuit includes multiple voltage regulation circuits, labeled 1 through n. Each voltage regulation circuit corresponds one-to-one to each of the multiple battery channels, and each voltage regulation circuit is connected in series with each of the single cells to form a battery channel, for example, labeled Channel 1 through Channel n.

[0049] Furthermore, the control circuit further includes a reference voltage generating circuit and a plurality of sub-control circuits, wherein the reference voltage generating circuit is connected to the multiple batteries and the multiple voltage regulating circuits to adjust the voltage according to the voltage drop of the multiple batteries (which can be recorded as V B1 To V Bn ) and the voltage drops of the plurality of voltage regulating circuits (which may be recorded as V A1 To V An ) obtain a reference voltage signal Vref; and multiple sub-control circuits, each corresponding to each of the multiple voltage regulation circuits. The multiple sub-control circuits receive the reference voltage signal and control the voltage drops of the multiple voltage regulation circuits accordingly, so that the total voltage drop of each battery channel is consistent with the voltage value of the reference voltage signal. Herein, the reference voltage generation circuit and the multiple sub-control circuits are collectively referred to as the main control circuit.

[0050] As can be seen from the above circuit block diagram, by selecting the maximum voltage drop among multiple battery channels, then adjusting the voltage regulator circuit corresponding to the channel with the maximum voltage drop value to obtain the minimum value, the difference between the two is used as the reference voltage signal. The voltage drops of the other battery channels are then adjusted according to this reference voltage signal to maintain the charge and discharge currents of each channel as balanced as possible. Because the maximum voltage drop is selected, the voltage drops of the other voltage regulator circuits are increased, making the voltage drops of each channel more consistent. Adjusting the voltage drop of the voltage regulator circuit is convenient and simple in circuit implementation, without adding additional components or costs.

[0051] During the battery charging and discharging process, the reference voltage is selected differently due to different control parameters. The following describes the generation process of the reference voltage signal during the charging and discharging processes respectively.

[0052] In one embodiment, the reference voltage generating circuit includes a first voltage generating circuit, a second voltage generating circuit and a first logic operation circuit. When the multi-channel battery is in a charging state, the first voltage generating circuit receives the voltage drop of the multi-channel battery and selects the voltage V with the maximum voltage drop value. BmaxAs the first voltage signal; the second voltage generating circuit obtains the minimum voltage drop value V of the voltage regulating circuit of the battery channel according to the battery channel corresponding to the maximum voltage drop selected by the first voltage generating circuit Amin , so as to use the voltage of the minimum voltage drop value as the second voltage signal; the logic operation circuit performs a superposition operation on the first voltage signal and the second voltage signal to obtain the first reference voltage signal, such as V ref1 =V Bmax +V Amin .

[0053] Preferably, the minimum voltage drop value of the voltage regulating circuit is zero or the difference between the minimum voltage drop value and zero is within a predetermined range, and the predetermined range is set according to the actual circuit conditions, for example, the predetermined range is 0 to 2V, but is not limited thereto.

[0054] In one embodiment, the voltage regulation circuit includes a switching circuit, such as Figure 3 As shown, the switching circuit is a first switching tube and a second switching tube connected in series. The first switching tube is configured to control the charging working state of the battery, and the second switching tube is configured to control the discharging working state of the battery. It should be noted that when the battery is in the charging state, the first switching tube acts as a regulating switch, and the second switching tube is in a fully conductive state. In the battery charging state, the sub-control circuit controls the switching circuit corresponding to the maximum voltage drop value to be fully conductive to obtain the minimum voltage drop value of the switching circuit. Here, the sub-control circuit controls the first switching tube and the second switching tube to be fully conductive. The logic operation circuit performs superposition operation on the first voltage signal and the second voltage signal to obtain the first reference voltage signal, such as V ref1 =V Bmax +V Amin .

[0055] From the above, we can know that V ref The path with the largest battery voltage drop can make the voltage adjustment of other paths more convenient. For example, increasing the voltage drop of other battery channels can make the voltage drops of each path tend to be consistent. Increasing the voltage drop is a relatively easy way to achieve in the circuit. For example, by increasing the impedance of the switch tube, when the same current flows through it, its voltage drop will increase, thereby increasing the total voltage drop of the channel. Figure 3As shown, the sub-control circuit generates a control signal Vn. After adjustment by the logic and drive circuits, the control signal Vn is used to drive the switching state of the first and second switching transistors, thereby adjusting the voltage drop. Here, after obtaining the voltage drop of the channel with the largest battery voltage drop as the first voltage signal, in order to facilitate the adjustment of the voltage drops of other channels, the voltage drop of the voltage regulation circuit of the channel with the largest battery voltage drop is set to be as small as possible, ideally zero. However, in practice, due to the inherent impedance of the switching transistor, the switching transistor is fully turned on to minimize the impedance of the switching transistor to achieve the minimum voltage drop.

[0056] In another embodiment, Figure 4 The voltage regulation circuit includes adjustable voltage sources, such as U1 to Un. When the battery is in the charging state, the sub-control circuit controls the voltage drop of the adjustable voltage source corresponding to the maximum voltage drop value to zero, thereby obtaining the minimum voltage drop value of the adjustable voltage source. Similar to the above principle, to ensure that the total reference voltage does not significantly affect the adjustment difficulty of other channels, the minimum voltage drop value of the adjustable voltage source is set to zero or close to zero.

[0057] In one embodiment, the reference voltage regulation circuit includes a third voltage generating circuit, a fourth voltage generating circuit and a second logic operation circuit. When the multi-channel battery is in a discharging state, the third voltage generating circuit receives the voltage drop of the multi-channel battery and selects the voltage V with the minimum voltage drop value. Bmin As the third voltage signal; the fourth voltage generating circuit obtains the minimum voltage drop value of the voltage regulating circuit of the battery channel according to the battery channel corresponding to the minimum voltage drop selected by the third voltage generating circuit, so as to convert the voltage V corresponding to the minimum voltage drop value into the voltage V Amin as a fourth voltage signal;

[0058] The logic operation circuit performs a subtraction operation on the third voltage signal and the fourth voltage signal to obtain a second reference voltage signal V ref2 =V Bmin -V Amin .by Figure 1 Taking the battery structure in as an example, since the voltage direction of the battery is opposite to the voltage direction of the voltage regulating circuit during the discharge process, the second reference voltage signal is set to V ref2 =V Bmin -V Amin The reference voltage signal value obtained is a reasonable value, so that other channels can easily adjust the voltage drop of the voltage regulation circuit and more easily obtain the reference voltage standard. Here, the minimum voltage drop value of the voltage regulation circuit is zero or the difference between the minimum voltage drop value and zero is within a predetermined range.

[0059] Specifically, in one embodiment, Figure 3 As shown, the voltage regulation circuit includes a switching circuit comprising a first switching transistor and a second switching transistor connected in series. The first switching transistor is configured to control the battery's charging state, and the second switching transistor is configured to control the battery's discharging state. It should be noted that when the battery is in the discharging state, the second switching transistor acts as a regulating switch, and the first switching transistor is fully conductive. In the battery's discharging state, the sub-control circuit controls the switching circuit corresponding to the minimum voltage drop value to be fully conductive. Here, both the first switching transistor and the second switching transistor are fully conductive to achieve the minimum voltage drop value for that switching circuit.

[0060] According to the above embodiment, when the total voltage drop corresponding to the minimum voltage drop value is used as the reference voltage signal, the sub-control circuits of the other battery channels control the voltage drop of the switch circuits, for example, by reducing the impedance of the second switch tube to reduce the voltage drop, so that the total voltage drop of the battery channels is consistent with the second reference voltage signal. The voltage adjustment and control during discharge is similar to that during charging and will not be repeated here.

[0061] In another embodiment, the voltage regulation circuit includes an adjustable voltage source. When the battery is in a discharging state, the sub-control circuit controls the voltage drop of the voltage-controlled voltage source corresponding to the minimum voltage drop value to zero, thereby obtaining the minimum voltage drop value of the switch circuit in that path. The beneficial effects of this embodiment are consistent with the beneficial effects of charging described above.

[0062] It should be noted that when the voltage regulation circuit is a switch circuit, the sub-control circuit controls the switch state of the switch circuit according to the overvoltage protection threshold or the undervoltage protection threshold, so that the battery operates in a non-overvoltage or non-undervoltage state. For example, the sub-control circuit uses two comparators to compare the detected battery voltage with the overvoltage threshold or the undervoltage threshold, and controls the switch state of the first switch tube or the second switch tube according to the comparison result, so that the battery does not experience overvoltage or undervoltage. It should be emphasized here that the switch circuit in the embodiment of the present invention can not only realize the function of overvoltage or undervoltage, but also serve as a voltage regulation function, so that the voltage during the charging or discharging process can be well adjusted to achieve charging or discharging balance. Without adding circuit components, multiple functions can be realized, with low cost and good effect.

[0063] Finally, the present invention also discloses a battery charge and discharge control method for controlling multiple parallel connected batteries, characterized in that it comprises the steps of: during the charging process of the multiple batteries,

[0064] detecting voltage drops of the multiple batteries and selecting a voltage with a maximum voltage drop value as a first voltage signal;

[0065] Utilize multiple voltage regulating circuits and the multiple batteries to be connected in series one by one to form multiple battery channels; obtain the minimum voltage drop value of the voltage regulating circuit corresponding to the maximum voltage drop value, and use the voltage of the minimum voltage drop value as the second voltage signal;

[0066] performing an addition operation on the first voltage signal and the second voltage signal to obtain a first reference voltage signal;

[0067] The voltage drop value of each voltage regulating circuit is adjusted according to the first reference voltage signal, so that the total voltage drop of each battery channel is consistent with the reference voltage signal.

[0068] Furthermore, the method further comprises the steps of: during the discharge process of the multi-channel battery,

[0069] detecting voltage drops of the multiple batteries and selecting a voltage with a minimum voltage drop value as the third voltage signal;

[0070] Obtaining a minimum voltage drop value of a voltage regulating circuit corresponding to the minimum voltage drop value, and using the voltage of the minimum voltage drop value as a fourth voltage signal;

[0071] performing a subtraction operation on the third voltage signal and the fourth voltage signal to obtain a second reference voltage signal;

[0072] The voltage drop value of each voltage regulating circuit is adjusted according to the second reference voltage signal, so that the total voltage drop of each battery channel is consistent with the second reference voltage signal.

[0073] Preferably, the minimum voltage drop value of the voltage regulating circuit is zero or the difference between the minimum voltage drop value and zero is within a predetermined range.

[0074] The above-described embodiments do not constitute a limitation on the scope of protection of this technical solution. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the above-described embodiments shall be included in the scope of protection of this technical solution.

Claims

1. A battery charge and discharge control circuit for controlling multiple batteries connected in parallel, characterized in that: include, a plurality of voltage regulating circuits, wherein the plurality of voltage regulating circuits correspond one to one with the plurality of battery channels, and each of the voltage regulating circuits is connected in series with each single battery to form a battery channel; A reference voltage generating circuit is connected to the multiple batteries and the multiple voltage regulating circuits to obtain a reference voltage signal according to the voltage drops of the multiple batteries and the voltage drops of the multiple voltage regulating circuits. multiple sub-control circuits, each corresponding to each of the multiple voltage regulating circuits, receiving the reference voltage signal and controlling the voltage drops of the multiple voltage regulating circuits accordingly, so that the total voltage drop of each battery channel is consistent with the voltage value of the reference voltage signal; The reference voltage generating circuit includes a first voltage generating circuit, a second voltage generating circuit and a first logic operation circuit. When the multi-channel battery is in a charging state: The first voltage generating circuit receives the voltage drops of the multi-channel batteries and selects the voltage with the maximum voltage drop value as the first voltage signal; The second voltage generating circuit obtains a minimum voltage drop value of a voltage regulating circuit of a battery channel corresponding to the maximum voltage drop selected by the first voltage generating circuit, and uses the voltage of the minimum voltage drop value as a second voltage signal; The logic operation circuit performs a superposition operation on the first voltage signal and the second voltage signal to obtain a first reference voltage signal.

2. The control circuit according to claim 1, wherein: The reference voltage regulating circuit includes a third voltage generating circuit, a fourth voltage generating circuit and a second logic operation circuit. When the multi-channel battery is in a discharging state: The third voltage generating circuit receives the voltage drop of the multi-channel battery and selects the voltage with the minimum voltage drop value as the third voltage signal; The fourth voltage generating circuit obtains a minimum voltage drop value of a voltage regulating circuit of a battery channel corresponding to the minimum voltage drop selected by the third voltage generating circuit, and uses a voltage corresponding to the minimum voltage drop value as a fourth voltage signal; The logic operation circuit performs a subtraction operation on the third voltage signal and the fourth voltage signal to obtain a second reference voltage signal.

3. The control circuit according to claim 1 or 2, characterized in that: The minimum voltage drop value of the voltage regulating circuit is zero, or the difference between the minimum voltage drop value and zero is within a predetermined range.

4. The control circuit according to claim 1, wherein: The voltage regulating circuit includes a switching circuit; In the battery charging state, the sub-control circuit controls the switch circuit corresponding to the maximum voltage drop value to be fully turned on to obtain the minimum voltage drop value of the switch circuit.

5. The control circuit according to claim 1, wherein: The voltage regulating circuit includes an adjustable voltage source; In the battery charging state, the sub-control circuit controls the voltage drop of the adjustable voltage source corresponding to the maximum voltage drop value to be zero, so as to obtain the minimum voltage drop value of the adjustable voltage source.

6. The control circuit according to claim 2, characterized in that: The voltage regulating circuit includes a switching circuit; In the battery charging state, the sub-control circuit controls the switch circuit corresponding to the minimum voltage drop value to be fully turned on to obtain the minimum voltage drop value of the switch circuit.

7. The control circuit according to claim 2, characterized in that: The voltage regulation circuit includes an adjustable voltage source; In the battery discharging state, the sub-control circuit controls the voltage drop of the voltage-controlled voltage source corresponding to the minimum voltage drop value to be zero, so as to obtain the minimum voltage drop value of the adjustable voltage source.

8. The control circuit according to claim 4 or 6, characterized in that: When the voltage regulating circuit is a switching circuit, The sub-control circuit controls the switching state of the switch circuit according to an overvoltage protection threshold or an undervoltage protection threshold, so that the battery operates in a non-overvoltage or non-undervoltage state.

9. A battery charge and discharge control method, implemented using the battery charge and discharge control circuit according to any one of claims 1 to 8, for controlling multiple batteries connected in parallel, characterized in that: Including steps: During the charging process of the multi-channel battery, detecting voltage drops of the multiple batteries and selecting a voltage with a maximum voltage drop value as a first voltage signal; Utilize multiple voltage regulating circuits and the multiple batteries to be connected in series one by one to form multiple battery channels; obtain the minimum voltage drop value of the voltage regulating circuit corresponding to the maximum voltage drop value, and use the voltage of the minimum voltage drop value as the second voltage signal; performing an addition operation on the first voltage signal and the second voltage signal to obtain a first reference voltage signal; The voltage drop value of each voltage regulating circuit is adjusted according to the first reference voltage signal, so that the total voltage drop of each battery channel is consistent with the reference voltage signal.

10. The control method according to claim 9, characterized in that: Including steps: During the discharge process of the multi-channel battery, detecting voltage drops of the multiple batteries and selecting a voltage with a minimum voltage drop value as a third voltage signal; Obtaining a minimum voltage drop value of a voltage regulating circuit corresponding to the minimum voltage drop value, and using the voltage of the minimum voltage drop value as a fourth voltage signal; performing a subtraction operation on the third voltage signal and the fourth voltage signal to obtain a second reference voltage signal; The voltage drop value of each voltage regulating circuit is adjusted according to the second reference voltage signal, so that the total voltage drop of each battery channel is consistent with the second reference voltage signal.

11. The control method according to claim 9 or 10, characterized in that: The minimum voltage drop value of the voltage regulating circuit is zero, or the difference between the minimum voltage drop value and zero is within a predetermined range.

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