CN111245068A - Battery system and control method with cooling equalization function - Google Patents

Abstract

The invention belongs to the technical field of batteries, and particularly discloses a battery system with a cooling equalization function and a control method, wherein the battery system comprises a battery pack and a cooling equalization system, a shell is arranged outside the battery pack, a signal acquisition unit and a control unit are arranged in the shell, and the signal acquisition unit is connected with the battery pack and is used for acquiring temperature and voltage information of the battery pack; the cooling equalization system comprises a refrigerating sheet set, and a power supply end of the refrigerating sheet set is connected with a battery pack or an external power supply end; the control unit controls the external power supply to output electric energy to the refrigerating sheet set for refrigeration, or the control unit controls the battery pack to output electric energy to the refrigerating sheet set to realize battery pack balance, and meanwhile, the refrigerating sheet set realizes refrigeration by utilizing the balance electric energy output by the battery pack. By adopting the technical scheme, the signal acquisition unit and the control unit are used for controlling the refrigerating sheet set to operate, so that the battery pack has quick balanced repair capability while charging, and the internal temperature rise caused by charging can be reduced.

Description

Battery system and control method with cooling equalization function

technical field

The invention belongs to the technical field of batteries, and relates to a battery system and a control method with a cooling equalization function.

Background technique

During the charging and discharging cycle of a multi-series battery pack, due to the difference in characteristics between the individual lithium batteries connected in series, the use of a period of time will cause an imbalance between the series-connected lithium batteries. Reduced service life. Therefore, it is necessary to perform balanced repair management on multi-string battery packs. At the same time, during the charging and discharging process of the battery pack, the temperature is a key factor affecting the life of the lithium battery. In the passive equalization charging stage of the currently known lithium battery, the equalizing load used is to convert excess electric energy into heat energy. The higher the balancing ability of the battery pack, the more heat is generated during balancing, which causes the battery pack balancing ability and temperature to become a contradiction. The traditional balancing method with low balancing heat has weak balancing ability and cannot meet the needs of real-time balancing repair of batteries. Using the traditional method to achieve higher balancing capability will lead to higher temperature of the battery system. At the same time, using the existing method to cool down will greatly increase the cost; if the temperature is not cooled, it will have a greater impact on the battery life and increase the safety hazard of the battery pack. .

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a battery system with a cooling equalization function and a control method, so as to achieve a better equalization effect, and at the same time, the battery pack can be cooled during the equalization process.

In order to achieve the above purpose, the basic solution of the present invention is: a battery system with a cooling equalization function, including a battery pack and a cooling equalization system, the battery pack is provided with a casing outside, and a signal acquisition unit and a signal acquisition unit are arranged in the casing. a control unit, the signal acquisition unit is connected to the battery pack and used to collect at least temperature information and voltage information of the battery pack, and the signal output end of the signal acquisition unit is connected to the corresponding information input end of the control unit;

The cooling and equalizing system includes a cooling chip group arranged on the casing, the power supply end of the cooling chip group is connected to the battery pack or the external power supply terminal through a power switch device, and the power switch device is connected to the control signal output end of the control unit. connect;

The control unit controls the external power supply to output electrical energy to the cooling chip group for cooling, or the control unit controls the battery pack to output electrical energy to the cooling chip group to achieve battery balance while the cooling chip group uses the power output from the battery to achieve cooling.

The working principle and beneficial effects of this basic scheme are as follows: the signal acquisition unit collects the temperature and voltage information of the battery pack, and then transmits the collected information to the control unit. Then, the control signal is output to the power switch device, and the cooling chip group is connected to the power supply, thereby starting the cooling of the cooling chip group. The cooling chip group can accept the power supply of the battery group or the external power supply terminal. When the battery group does not need to be balanced, the external power supply can provide power for the cooling chip group, ensuring that when the cooling chip group needs to be cooled, the operation can be started smoothly; when the control unit determines that the battery group needs When balancing is performed, the control unit controls the power switch device to conduct, so that the cooling chip group and the battery group are connected, the cooling chip group acts as a balanced load, the control unit controls the excess power in the battery pack to be input into the cooling chip group, and the cooling chip group consumes the excess electric energy. , so that the battery pack can be quickly balanced, and at the same time, the cooling chip pack consumes electricity to achieve heat absorption and cooling, preventing overheating during the battery pack balancing process and affecting the service life of the battery pack, and achieving a better balance effect.

Further, the refrigerating sheet group is embedded on the casing, both sides of the refrigerating sheet group are fitted with heat exchangers, and the heat exchanger on the side away from the inside of the casing protrudes out of the casing.

The heat exchanger can improve the heat transfer capacity between the refrigerating sheet group and the shell, speed up the cooling speed, and ensure the normal operation of the equipment. At the same time, the heat exchanger and the refrigerating sheet group are arranged in close contact, so that the refrigerating sheet group and the heat exchanger are in direct contact, which is more conducive to heat transfer. And a heat exchanger on the refrigeration fin group extends out of the casing, so that the heat on the refrigeration fin group can be discharged out of the casing and dissipated in time.

Further, the part where the refrigeration sheet group is attached to the heat exchanger is coated with a thermally conductive material.

Thermally conductive materials can increase the heat transfer capacity between the cooling fin pack and the heat exchanger.

Further, the refrigerating sheet group is attached to the outer wall or the inner wall of the casing.

According to the shape and size of the battery pack casing, the cooling fins are designed outside the casing and absorb heat through the casing; the cooling fins are designed inside the casing, the heating surface is close to the casing, and the heat is dissipated through the casing, so there is no need to set up heat switch, saving costs.

Further, the part where the cooling sheet group is attached to the casing is coated with a thermally conductive material.

The thermally conductive material is more conducive to the heat transfer between the cooling plate group and the shell, and optimizes the heat dissipation effect.

The present solution also provides a control method for the battery system with a cooling equalization function as described above, comprising the following steps:

During the charging process of the battery pack, the positive voltage V _2ij of each battery pack of the battery pack is collected by the signal acquisition unit, 1≤i≤m, 1≤j≤n, m is the number of rows of the battery pack, and n is the number of columns of the battery pack , m≥1, n≥1;

The battery pack voltage collection of the battery pack uses the common ground principle, set the equalization turn-on voltage V ₁ and the full charge voltage drop a of each battery pack, calculate V = V _2ij -(mi)×a, if V reaches the preset value V ₁ , and the control unit turns on the balancing load corresponding to the battery pack that has reached the preset value for balancing.

When in the equalization stage, the control unit controls the cooling plate group as an equalizing load, consumes the excess power of the battery group, and cools the battery group at the same time. Since all or part of the battery packs of the battery pack are in a series structure, the negative pole of one battery pack is the positive pole of the other battery pack between adjacent batteries. By using the balancing method of the present invention, it can not only ensure that the positive pole voltage of all battery packs is the same as that of the other battery pack. It is constant and can ensure the charging voltage of each battery pack to be constant at the same time. One method realizes at least these two functions at the same time, which greatly improves the service life of the battery.

Description of drawings

FIG. 1 is a schematic diagram of a hardware circuit in a casing of an embodiment of a battery system with a cooling equalization function of the present invention.

Reference numerals: refrigeration sheet group 1 , heat exchanger 2 .

Detailed ways

The following describes in detail the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, only used to explain the present invention, and should not be construed as a limitation of the present invention.

In the description of the present invention, it should be understood that the terms "portrait", "horizontal", "upper", "lower", "front", "rear", "left", "right", "vertical", The orientations or positional relationships indicated by "horizontal", "top", "bottom", "inside", "outside", etc. are based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than An indication or implication that the referred device or element must have a particular orientation, be constructed and operate in a particular orientation, is not to be construed as a limitation of the invention.

In the description of the present invention, unless otherwise specified and limited, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it may be a mechanical connection or an electrical connection, or two The internal communication between the elements may be directly connected or indirectly connected through an intermediate medium, and those of ordinary skill in the art can understand the specific meanings of the above terms according to specific circumstances.

The embodiment is shown in Figure 1: the present invention discloses a battery system with a cooling equalization function, and the battery system with a cooling equalization function includes a plurality of battery packs (single cells or parallel battery modules, hereinafter referred to as battery packs) With the cooling equalization system, multiple battery packs are preferably arranged in series, and the battery pack can be a battery pack of any material, specifically, but not limited to, a lithium battery pack. The battery pack is provided with a casing outside, and the casing is provided with a signal acquisition unit and a control unit. The specific signal acquisition unit and control unit can be set separately or integrated into one set (for example, the signal acquisition and control unit in Figure 1 is an integrated set. ), the signal acquisition unit includes but is not limited to temperature sensor (such as PT100) and voltage sensor (such as MIK-DZV single-phase DC voltage sensor) and/or current sensor (such as SZ1K-50 Hall-type current sensor), signal acquisition unit It is close to the battery pack (such as the connection method of the temperature sensor) or electrically connected to the battery pack (such as the connection method of the voltage sensor and the current sensor), which is used to collect the temperature information and voltage information of the battery pack and transmit it to the control unit, or collect the battery pack. The temperature information and current information of the group are transmitted to the control unit.

The number of specific voltage sensors is provided in multiples, and the voltages detected by the voltage sensors correspond to the batteries one-to-one. In a more preferred embodiment, each voltage sensor detects its corresponding positive voltage of the battery.

In a preferred embodiment of the present invention, the signal collection unit collects temperature information and voltage information of the battery pack and transmits them to the control unit. The control unit includes a first type of comparator and a second type of comparator, the output end of the temperature sensor is electrically connected to the first input end of the first type of comparator, and the second input end of the first type of comparator is connected with a temperature threshold memory ; The output end of the voltage sensor is electrically connected to the first input end of the second type of comparator, and the second input end of the second type of comparator is connected to the voltage threshold memory. The first type of comparator and the second type of comparator are preferably but not limited to LM324 and LM339.

The cooling and equalizing system includes a cooling chip group 1 arranged on the casing, and the cooling chip group 1 adopts semiconductor cooling chips. According to the needs of the user, the cooling chip group 1 can be embedded on the shell, the heat exchanger 2 is attached to both sides of the cooling chip group 1, and the heat exchanger 2 on the side far from the inside of the shell extends out of the shell, Moreover, the parts where the cooling fin group 1 and the heat exchanger 2 are attached are coated with thermally conductive material, the heat exchanger 2 can improve the heat transfer capacity between the cooling fin group 1 and the shell, and has better heat dissipation effect, but the cost is relatively high. The cooling chip group 1 can also be attached to the outer wall or inner wall of the casing, and the cooling chip group 1 is fixedly connected to the shell (such as welding or bonding), and also the part where the cooling chip group 1 is attached to the shell is coated with heat conduction. Materials (such as thermal conductive silicone grease, etc.), through the contact between the cooling sheet group 1 and the shell, heat transfer is carried out, no heat exchanger 2 is needed, the manufacturing cost is reduced, and the relationship between the sealing performance of the battery pack assembly and the heat dissipation performance is objectively solved. the contradiction.

In this embodiment, the power supply terminal of the cooling chip group 1 is electrically connected to the battery pack or an external power source through a power switch device. The power switch device includes a first switch and a second switch, and the first switch is arranged between the cooling chip group and the external power source. The number of the second switches corresponds to the number of the battery packs, and the first switch and the second switch are respectively The first switch and the second switch are preferably but not limited to switching devices such as MOS transistors, IGBTs, relays, and triodes, which are correspondingly electrically connected to the output ends of the first type of comparator and the second type of comparator.

The output terminal of the first type of comparator is connected to the control terminal of the first switch, and the output terminal of the second type of comparator is connected to the corresponding control terminal of the second switch. The control unit controls the external power supply to output electrical energy to the cooling chip group 1 for cooling, or the signal acquisition and control unit controls the battery pack to output electrical energy to the cooling chip group 1 to achieve battery balance, and the cooling chip group 1 uses the power output from the battery pack to achieve cooling.

The present solution also provides a control method for the battery system with a cooling equalization function as described above, comprising the following steps:

During the charging process of the battery pack, the positive voltage V _2ij of each battery pack of the battery pack is collected by the signal acquisition unit, 1≤i≤m, 1≤j≤n, m is the number of rows of the battery pack, and n is the number of columns of the battery pack , m≥1, n≥1;

The voltage acquisition of the battery pack uses the common ground principle, set the equalization turn-on voltage V ₁ and the full charge voltage drop a of each battery pack, calculate V=V _2ij -(mi)×a, if V reaches the preset value V ₁ , control The unit turns on the balancing load corresponding to the battery pack that has reached the preset value for balancing. When in the equalization stage, the control unit controls the cooling plate group as an equalizing load, consumes the excess power of the battery group, and cools the battery group at the same time.

The number of temperature sensors is one or more, and when the number of temperature sensors is more than one, the number of temperature sensors is the same as that of the first type of comparators and corresponds one-to-one.

After the above judgment method, when the battery pack does not need to be balanced, the signal acquisition unit detects that the temperature of the battery pack is too high, and the temperature sensor transmits the temperature information to its corresponding first-type comparator. When the input temperature signal exceeds the temperature threshold, the The first type of comparator outputs a control signal to the first switch, the first switch is closed, and the corresponding refrigeration chip group 1 is powered on to start, and the refrigeration chip group 1 uses an external power source for cooling. Specifically, a relay can be used as the first switch, the input loop of the relay is connected to the output end of the first type of comparator, and the normally open contact of the relay is connected in series with the power supply loop of the external power supply to supply power to the refrigeration chip group. When using the external power supply for cooling, the temperature sensor detects the temperature value of the battery pack in real time and transmits it to the first type of comparator. When the temperature of the battery pack is lower than or equal to the threshold value, the first switch is turned on, and the external power supply stops connecting to the cooling chip pack. 1 power supply.

When the battery pack is balanced according to the above method, there should be multiple comparators of the second type and multiple switches of the second type, and the number of the comparators of the second type and the second switches should be the same as the number of battery packs in the battery pack , so that the second type of comparator can correspond to the battery pack one-to-one. Similarly, multiple voltage sensors and/or current sensors also need to be set up so that they correspond to the battery pack one-to-one to realize the collection of the voltage of each battery pack. And each second type of comparator needs to be electrically connected to the corresponding cooling chip through a second switch, and the number of the second switches is equal to the number of the comparators.

Taking a second switch and a second type comparator connected to it as an example, when the voltage signal received by the second type comparator is greater than the preset value in the voltage threshold memory, the second type comparator outputs a control signal To the corresponding second switch, the second switch is controlled to be closed, so that the cooling chip corresponding to the second switch is connected to the corresponding battery pack. The refrigerating sheet group 1 consumes excess electric energy to quickly balance the battery pack, while the cooling sheet group 1 consumes electric energy to achieve endothermic cooling, preventing overheating during the balancing process of the battery pack and affecting the service life of the battery pack, and achieving a better balancing effect.

Specifically, a relay can be used as the second switch, the input circuit of the relay is connected to the output end of the second comparator, and the normally open contacts of the relay are connected in series in the power supply circuit of the battery pack to supply power to the refrigeration chip pack. When performing equalization, the voltage sensor detects the voltage value of the battery pack in real time and transmits it to the second type of comparator. When the battery pack voltage is higher than the threshold value, the second type of comparator outputs an on signal, the relay coil is energized, and its normally open contact When the battery pack is closed, the battery pack supplies power to the cooling sheet pack 1 for voltage equalization; when the battery pack voltage is lower than or equal to the threshold, the second switch is turned on, and the battery pack stops supplying power to the cooling sheet pack 1 . In this embodiment, different comparators have different thresholds in the voltage threshold memory. For example, the comparator C _ij collects the positive voltage V _2ij of the i-th row and j-column battery pack, and the threshold value stored in the threshold memory is (mi)×a.

In this method, not only the voltage drop of each battery pack meets the requirements, but also the positive pole of each battery pack, no matter how the negative pole voltage of the battery pack drifts, the positive pole voltage when the balance is turned on is also constant. Service life and balanced restoration are extremely beneficial.

In the description of this specification, description with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., mean specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, The scope of the invention is defined by the claims and their equivalents.

Claims (6)

1. A battery system with a cooling equalization function is characterized by comprising a battery pack and a cooling equalization system, wherein a shell is arranged outside the battery pack, a signal acquisition unit and a control unit are arranged in the shell, the signal acquisition unit is connected with the battery pack and used for at least acquiring temperature information and voltage information of the battery pack, and a signal output end of the signal acquisition unit is connected with a corresponding information input end of the control unit;

the cooling equalization system comprises a refrigerating sheet set arranged on the shell, a power supply end of the refrigerating sheet set is connected with the battery pack or an external power supply end through a power switch device, and the power switch device is connected with a control signal output end of the control unit;

the control unit controls the external power supply to output electric energy to the refrigerating sheet set for refrigeration, or the control unit controls the battery pack to output electric energy to the refrigerating sheet set to realize battery pack balance, and meanwhile, the refrigerating sheet set realizes refrigeration by using the electric energy output by the battery pack.

2. The battery system with the cooling and balancing functions as claimed in claim 1, wherein the cooling fin set is embedded in the housing, the heat exchangers are attached to both sides of the cooling fin set, and the heat exchanger on the side far away from the inside of the housing extends out of the housing.

3. The battery system with the cooling equalization function as claimed in claim 2, wherein the part of the refrigerating fin group attached to the heat exchanger is coated with a heat conduction material.

4. The battery system with cooling equalization function as claimed in claim 1, wherein the cooling fin group is attached to the outer wall or the inner wall of the housing.

5. The battery system with the cooling and equalizing functions as claimed in claim 4, wherein the portion of the cooling fin group attached to the housing is coated with a heat conducting material.

6. A control method of a battery system having a cool-down leveling function according to any one of claims 1 to 5, comprising the steps of:

in the charging process of the battery pack, the signal acquisition unit acquires the positive voltage V of each battery pack of the battery pack_2ijI is more than or equal to 1 and less than or equal to m, j is more than or equal to 1 and less than or equal to n, m is the number of rows of the battery pack, n is the number of columns of the battery pack, m is more than or equal to 1, and n is more than or equal to 1;

the voltage acquisition of the battery pack uses the common ground principle, and the equalizing starting voltage V is set₁And the full charge voltage drop a of each battery pack, and calculating V-V_2ij- (m-i). times.a if V reaches a predetermined value V₁And the control unit switches on the balance load corresponding to the battery pack which reaches the preset value for balancing.

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