Battery charging device and battery system

Abstract

The utility model belongs to the technical field of battery heating, and particularly relates to a battery charging device and a battery system. The battery charging device comprises a heating loop and a charging loop, a first switch and charging equipment are arranged on the charging loop in series, a second switch is further arranged on the charging loop, and an anti-reverse module is arranged on the second switch in parallel. The anti-reverse module is used for preventing current from flowing from the charging equipment to the battery when the charging equipment detects voltage at two ends of the battery, thereby effectively preventing damage of low-temperature charging to the battery, improving use safety of the battery and prolonging service life of the battery. The problem that the battery is damaged due to irreversible overcharge of the battery caused by charging current when the temperature of the battery is low and the battery does not have the allowable charging capability is solved.

Description

Technical Field

[0001] The utility model belongs to the technical field of battery heating, and in particular relates to a battery charging device and a battery system. Background Art

[0002] With the development of new energy vehicles, pure electric vehicles are becoming more and more popular. Lithium-ion batteries are the power source of pure electric vehicles. Batteries will inevitably encounter low temperature environments during use. Charging lithium-ion batteries at low temperatures may cause lithium ion precipitation and deposition. The deposited metallic lithium is prone to irreversible reactions with the electrolyte. While consuming a large amount of electrolyte, it will also further increase the thickness of the solid electrolyte membrane, resulting in further increases in the impedance of the battery's negative electrode surface membrane, and the battery polarization is enhanced again, causing irreversible damage to the battery, seriously affecting the battery's service life, and even causing safety accidents.

[0003] To this end, a battery charging device for low temperature charging is proposed in the prior art, such as Figure 1 As shown, it includes a heating circuit for low-temperature heating and a charging circuit for charging. Because the charging device of the charging circuit first determines the total voltage across the battery to adjust the output voltage before charging, it is necessary to close switches KM1 and KM2, causing the charging current to flow to the battery. If the battery temperature is low at this time and does not allow charging, the current will damage the battery, affecting the safety and service life of the battery. Utility Model Content

[0004] The utility model aims to provide a battery charging device and a battery system, so as to solve the problem in the prior art that when the battery is at a low temperature, the charging current of the charging device flows to the battery, causing damage to the battery.

[0005] In order to solve the above technical problems, the utility model provides a battery charging device, including a heating circuit and a charging circuit, wherein a first switch and a charging device are arranged in series on the charging circuit, and the utility model is characterized in that a second switch is also arranged on the charging circuit, and an anti-reverse module is arranged in parallel on the second switch, and the anti-reverse module is used to prevent current from flowing from the charging device to the battery when the charging device detects the voltage at both ends of the battery.

[0006] Furthermore, the anti-reverse module is a diode.

[0007] Furthermore, the first switch and the second switch are contactor switches.

[0008] Furthermore, the heating circuit is arranged in parallel at two ends of the charging device, and one end of the second switch is connected to the battery.

[0009] Furthermore, a heating module, a heating switch and a fuse are arranged in series on the heating circuit.

[0010] The beneficial effects of the above technical solution are as follows: the utility model is an improved invention, by connecting a second switch and an anti-reverse module arranged in parallel in the charging circuit, the second switch is disconnected during charging, and the charging device first determines the total battery voltage to adjust the output voltage before charging. The anti-reverse module can effectively prevent the charging current from flowing to the battery, and at the same time does not affect the charging device's detection of the total voltage at both ends of the battery, thereby avoiding the damage to the battery caused by the charging current flowing to the battery when the battery temperature is low and does not have the charging capacity to allow, thereby improving the battery's safety and service life.

[0011] In order to solve the above technical problems, the utility model also provides a battery system, including a battery, a heating circuit and a charging circuit, wherein a first switch and a charging device are arranged in series on the charging circuit, and the utility model is characterized in that a second switch is also arranged on the charging circuit, and an anti-reverse module is arranged in parallel on the second switch, and the anti-reverse module is used to prevent current from flowing from the charging device to the battery when the charging device detects the voltage across the battery.

[0012] Furthermore, the anti-reverse module is a diode.

[0013] Furthermore, the first switch and the second switch are contactor switches.

[0014] Furthermore, the heating circuit is arranged in parallel at two ends of the charging device, and one end of the second switch is connected to the battery.

[0015] Furthermore, a heating module, a heating switch and a fuse are arranged in series on the heating circuit.

[0016] The beneficial effects of the above technical solution are as follows: the utility model is an improved invention, by connecting a second switch and an anti-reverse module arranged in parallel in the charging circuit, the second switch is disconnected during charging, and the charging device first determines the total battery voltage to adjust the output voltage before charging. The anti-reverse module can effectively prevent the charging current from flowing to the battery, and at the same time does not affect the charging device's detection of the total voltage at both ends of the battery, thereby avoiding the damage to the battery caused by the charging current flowing to the battery when the battery temperature is low and does not have the charging capacity to allow, thereby improving the battery's safety and service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a circuit schematic diagram of a battery charging device in the prior art;

[0018] Figure 2 The utility model is a battery charging device circuit diagram of the battery charging device embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the utility model clearer, the specific implementation methods of the utility model are further described below in conjunction with the accompanying drawings.

[0020] The utility model does not affect the discharge performance of the existing battery system, the charging performance of the charging circuit and the heating performance of the heating circuit. By adding a second switch and an anti-reverse module arranged in parallel in the charging circuit, the second switch is disconnected during charging. When the charging device first determines the total voltage of the battery to adjust the output voltage before charging, the anti-reverse module can effectively prevent the charging current from flowing to the battery, and does not affect the detection of the total voltage at both ends of the battery by the charging device, thereby avoiding the damage to the battery caused by the charging current flowing to the battery when the battery temperature is low and does not have the charging capacity allowed, thereby improving the safety and service life of the battery.

[0021] Battery Charging Device Embodiment

[0022] The battery charging device includes a heating circuit and a charging circuit. A first switch, a second switch and a charging device are arranged in series on the charging circuit. An anti-reverse module is arranged in parallel on the second switch. The anti-reverse module is used to prevent current from flowing from the charging device to the battery when the charging device detects the voltage across the battery. A heating module, a heating switch and a fuse are arranged in series on the heating circuit. The heating module is a device that can heat the battery, such as a heating film or a heating plate. The heating circuit is arranged in parallel at both ends of the charging device, and one end of the second switch is connected to the battery. The anti-reverse module is a diode. In other embodiments, the anti-reverse module can be other devices that can prevent the charging current from flowing to the battery and can not affect the charging device to detect the total voltage across the battery. The form of the battery is not limited, and it can be various power supply systems. In this embodiment, the battery is a power battery pack, which includes multiple power battery cells.

[0023] As an implementation method, Figure 2 As shown, the charging circuit is provided with a first switch KM1 connected in series with one end of the battery, and a second switch KM4 connected in series with the other end of the battery, the heating circuit is provided with a heating module, a heating switch KM3 and a fuse in series, and the charging circuit is also provided with a charging device and a charging switch KM2 in series.

[0024] The first switch, the second switch, the charging switch and the heating switch are manual switches or automatic switches. Preferably, the above switches are contactor switches. The first switch is a main negative contactor switch, the second switch is a main positive contactor switch, the charging switch is a charging contactor switch, and the heating switch is a heating contactor switch. One end of the main negative contactor switch contact is connected to the negative pole of the battery, and the other end is connected to one end of the low-temperature heating circuit. One end of the main positive contactor switch contact is connected to the positive pole of the battery, and the other end is connected to the other end of the low-temperature heating circuit. The battery management system (not shown in the figure) is used to detect the battery temperature and connect the above contactor switches respectively to control the on and off of the above contactor switches.

[0025] The battery charging device of the utility model can prevent the charging current from flowing into the battery when the battery temperature is low and does not have the charging capacity to allow, thereby causing irreversible damage to the battery. The principle is:

[0026] Turn on the charging equipment, close the main negative contactor switch KM1 and the charging contactor switch KM2, and open the main positive contactor switch KM4. The charging equipment detects the total voltage across the power battery pack and obtains the minimum temperature Tmin of the power battery cell at the same time;

[0027] The charging device adjusts the output voltage of the charging device according to the detected total voltage across the power battery pack, and compares the minimum temperature Tmin with the preset heating start threshold T1. When the minimum temperature Tmin is lower than the preset heating start threshold T1 (i.e., Tmin<T1), the main negative contactor switch KM1 is disconnected, the charging contactor switch KM2 is kept closed, and the heating contactor switch KM3 is closed. The charging device is used directly to power the heating film, thereby heating the power battery. This can not only quickly heat up the battery temperature, but also isolate the power battery to avoid charging the power battery due to fluctuations in the heating film power at low temperatures.

[0028] When the heating film heats the lowest temperature of the power battery cell to the preset power battery chargeable temperature threshold T2 (i.e., Tmin≥T2), the heating mode is exited, the main positive contactor switch KM4 and the main negative contactor switch KM1 are closed, and normal charging of the power battery pack is realized. The power battery chargeable temperature threshold is greater than the preset heating start threshold (i.e., T2>T1).

[0029] Battery System Embodiment

[0030] The utility model also provides a battery system, including a battery and a battery charging device. The battery can be connected to a load to supply power to the load. The battery charging device is the device described in the above-mentioned battery charging device embodiment and will not be described in detail here.

[0031] The battery charging device and battery system of the utility model first judge the total voltage of the battery to adjust the output voltage before the charging device is charged, and disconnects the main positive contactor switch KM4 of the power battery. When the temperature of the battery is very low and does not allow charging capacity, the anti-reverse diode can effectively prevent the charging current from flowing to the battery, and at the same time does not affect the charging device to detect the total voltage at both ends of the battery, thereby avoiding the charging current flowing to the battery when the battery temperature is low and does not allow charging capacity, causing irreversible damage to the battery.

Claims

1. A battery charging device, comprising a heating circuit and a charging circuit, wherein a first switch and a charging device are connected in series on the charging circuit, characterized in that: The charging circuit is also provided with a second switch, and the second switch is provided with an anti-reverse module in parallel, and the anti-reverse module is used to prevent current from flowing from the charging device to the battery when the charging device detects the voltage at both ends of the battery.

2. The battery charging device according to claim 1, characterized in that: The anti-reverse module is a diode.

3. The battery charging device according to claim 1 or 2, characterized in that: The first switch and the second switch are contactor switches.

4. The battery charging device according to claim 3, characterized in that: The heating circuit is arranged in parallel at two ends of the charging device, and one end of the second switch is connected to the battery.

5. The battery charging device according to claim 1, characterized in that: The heating circuit is provided with a heating module, a heating switch and a fuse in series.

6. A battery system, comprising a battery, a heating circuit and a charging circuit, wherein a first switch and a charging device are connected in series on the charging circuit, characterized in that: The charging circuit is also provided with a second switch, and the second switch is provided with an anti-reverse module in parallel, and the anti-reverse module is used to prevent current from flowing from the charging device to the battery when the charging device detects the voltage at both ends of the battery.

7. The battery system according to claim 6, characterized in that: The anti-reverse module is a diode.

8. The battery system according to claim 6 or 7, characterized in that: The first switch and the second switch are contactor switches.

9. The battery system according to claim 8, characterized in that: The heating circuit is arranged in parallel at two ends of the charging device, and one end of the second switch is connected to the battery.

10. The battery system according to claim 6, characterized in that: The heating circuit is provided with a heating module, a heating switch and a fuse in series.

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