Internal heating method suitable for power battery pack

A power battery pack, power battery technology, applied in the direction of secondary batteries, secondary battery repair/maintenance, circuits, etc., can solve problems such as uneven preheating, and achieve the effect of uniform heating

Active Publication Date: 2019-06-28
HARBIN UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The present invention aims to solve the problem that an additional preheating circuit needs to be added and the preheating is uneven in the ext

Method used

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  • Internal heating method suitable for power battery pack
  • Internal heating method suitable for power battery pack
  • Internal heating method suitable for power battery pack

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Experimental program
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Effect test

specific Embodiment approach 1

[0019] Specific embodiment one: the following combination figure 1 and figure 2 Illustrating this embodiment, an internal heating method suitable for a power battery pack described in this embodiment, the power battery pack described in the method includes an even number of power batteries, and each two groups of power batteries is a self-heating unit, The charging and discharging signal terminals of one group of power batteries of each heating unit are connected to the signal input and output terminals of one side of the bidirectional DC / DC converter 2 , and the charging and discharging signal terminals of the other group of power batteries are connected to the other side of the bidirectional DC / DC converter 2 . side signal input and output;

[0020] No. 1 sampling circuit 1 and No. 2 sampling circuit 3 are respectively used to collect the temperature, terminal voltage, internal current of the power battery and the state of charge of the power battery of the two groups of p...

specific Embodiment approach 2

[0028] Specific embodiment two: the following combination image 3 This embodiment is described. This embodiment further describes an internal heating method suitable for a power battery pack described in Embodiment 1. The first-order Thevenin equivalent circuit model described in Step 3 includes an ohmic internal resistance R 0 , polarization resistance R 1 , polarization capacitance C 1 and an open-circuit equivalent voltage source U OC ;

[0029] Ohmic resistance R 0 One end is connected to the positive pole of the charging power supply, and the ohmic internal resistance R 0 The other end of the polarized capacitor C is also connected 1 one end and polarization resistance R 1 one end of the polarized capacitor C 1 The other end is simultaneously connected with the polarization resistor R 1 The other end of the open-circuit equivalent voltage source U OC positive, open-circuit equivalent voltage source U OC The negative pole is connected to the negative pole of the...

specific Embodiment approach 3

[0030] Embodiment 3: This embodiment further describes an internal heating method suitable for power battery packs described in Embodiment 2. The formula of the first-order Thevenin equivalent circuit model described in Step 3 is:

[0031]

[0032] where R 0 is the ohmic internal resistance, R 1 is the polarization internal resistance, C 1 is the polarized capacitance, U OC is the open-circuit voltage of the lithium-ion battery, U is the terminal voltage of the lithium-ion battery, and s is the complex frequency.

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Abstract

The invention discloses an internal heating method suitable for a power battery pack and relates to the technical field of lithium ion power battery heating. The invention solves the problems that anexterior preheating mode which is commonly used for a conventional power battery for preheating needs an additional preheating circuit and is not uniform in preheating. Through the large self-impedance of a lithium battery at low temperature, an alternating excitation current with adjustable frequency is generated between the two groups of power batteries through a bidirectional DC/DC, so that theinterior of the lithium battery is self-heated to a proper working temperature. Thus, an external heating device is not needed, an excitation source does not need to be additionally arranged, and only the bidirectional DC/DC converter needs to be arranged between the two sets of batteries. By controlling the switching frequency, namely the alternating excitation frequency, of the conduction direction of the bidirectional DC/DC converter, the two batteries are excited and heated at the same time. The optimal alternating excitation frequency for heating is calculated by establishing an equivalent circuit model of the battery to control the switching frequency of the bidirectional DC/DC converter. The preheating method is suitable for preheating the lithium ion power battery.

Description

technical field [0001] The invention relates to the technical field of lithium ion power battery heating. Background technique [0002] With the emergence of energy problems, the state strongly supports the new energy industry. Lithium-ion batteries have become an important energy storage element due to their advantages of high energy density, low self-discharge rate and no memory effect. It has been widely used in new energy power stations, electric vehicles and other fields. [0003] Due to the internal structure and electrochemical properties of lithium batteries, the charge-discharge performance of lithium batteries at low temperatures has great problems. At low temperature, the activity of the active material decreases, and the diffusion rate inside decreases. As a result, the internal impedance of the lithium-ion battery is greatly increased at low temperatures, the output power is reduced, and the available battery capacity is correspondingly reduced. At the same ...

Claims

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Application Information

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IPC IPC(8): H01M10/615H01M10/625H01M10/633H01M10/42
CPCY02E60/10
Inventor 吴晓刚崔智昊
Owner HARBIN UNIV OF SCI & TECH
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